Add lesson 61

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>

13 files changed, 804 insertions, 0 deletions

diff --git a/Lessons/Lesson_61/README.md b/Lessons/Lesson_61/README.md
new file mode 100644
index 0000000..f0ef50b
--- /dev/null
+++ b/Lessons/Lesson_61/README.md
@@ -0,0 +1,420 @@
+UEFI shell has a `dmpstore` command that helps to see content of UEFI variables.
+
+If you'll look at the help of the `dmpstore` command you could see one more useful feature that this command presents. With this command it is possible to save UEFI variables to a file and load them back from such files:
+```
+FS0:\> dmpstore -?
+...
+DMPSTORE [-all | ([variable] [-guid guid])] [-s file]
+DMPSTORE [-all | ([variable] [-guid guid])] [-l file]
+...
+  -s       - Saves variables to a file.
+  -l       - Loads and sets variables from a file.
+...
+```
+Let's try to use this mechanics to modify content of an existing UEFI variable. It can be a useful feature for the debug.
+
+In some earlier lesson we've created the `ShowBootVariables.efi` application that displays boot sources based on the content of UEFU boot variables:
+```
+FS0:\> ShowBootVariables.efi
+Boot0000
+UiApp
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
+
+Boot0001
+UEFI QEMU DVD-ROM QM00003
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+
+Boot0002*
+EFI Internal Shell
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(7C04A583-9E3E-4F1C-AD65-E05268D0B4D1)
+
+Boot0003
+UEFI QEMU HARDDISK QM00001
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+```
+
+One of the variables that were parsed in this application is a `BootOrder` variable. Just in case you forgot:
+```
+The BootOrder variable contains an array of UINT16’s that make up an ordered list of the Boot####
+options. The first element in the array is the value for the first logical boot option, the second element is
+the value for the second logical boot option, etc. The BootOrder order list is used by the firmware’s
+boot manager as the default boot order.
+```
+
+Print the content of the BootOrder variable
+```
+FS0:\> dmpstore BootOrder
+Variable NV+RT+BS 'EFIGlobalVariable:BootOrder' DataSize = 0x08
+  00000000: 00 00 01 00 02 00 03 00-                         *........*
+```
+This means that the order is:
+```
+Boot0000
+Boot0001
+Boot0002
+Boot0003
+```
+Everything is like our `ShowBootVariables` application shows.
+
+With a help of the `dmpstore` command we can dump the content of a `BootOrder` variable to a file:
+```
+FS0:\> dmpstore BootOrder -s BootOrder.bin
+Save variable to file: BootOrder.bin.
+Variable NV+RT+BS '8BE4DF61-93CA-11D2-AA0D-00E098032B8C:BootOrder' DataSize = 0x08
+```
+
+UEFI shell contains `hexedit` command in itself. With it we can see the content of a created file:
+
+![hexediti_1.png](hexedit_1.png?raw=true "BootOrder.bin before modifications")
+
+`hexedit` is a hex editor, you can see its help message with a `Ctrl+E` command:
+
+![hexedit_help.png](hexedit_help.png?raw=true "hexedit help")
+
+Exit help with `Ctrl-W`.
+
+`dmpstore` command represents each variable with a following structure in a file:
+```
+{
+  UINT32 NameSize;           // Size of the variable name in bytes
+  UINT32 DataSize;           // Size of the variable data in bytes
+  CHAR16 Name[NameSize/2];   // Variable name in CHAR16
+  EFI_GUID Guid;             // Variable GUID
+  UINT32 Attributes;         // Variable attributes
+  UINT8 Data[DataSize];      // Variable data
+  UINT32 Crc;                // CRC32 checksum for the record
+}
+```
+
+Here is a file content with a highlight for the structure fileds:
+
+![bootorder.png](bootorder.png?raw=true "bootorder")
+
+Let's try to modify the file content changing the boot order to:
+```
+Boot0001
+Boot0000
+Boot0002
+Boot0003
+```
+
+![hexedit_2.png](hexedit_2.png?raw=true "hexedit after modification")
+
+Type `Ctrl+Q` to quit and enter `y` to save our modifications.
+
+If you'll try to load the changed settings you would get an error:
+```
+FS0:\> dmpstore -l BootOrder.bin
+Load and set variables from file: BootOrder.bin.
+dmpstore: Incorrect file format.
+dmpstore: No matching variables found. Guid 8BE4DF61-93CA-11D2-AA0D-00E098032B8C
+```
+This is happening because `UINT32 Crc` field of the record is not longer valid for the current record content.
+
+Let's create an application `UpdateDmpstoreDump` to update CRC fields in the `dmpstore` dumps.
+
+Once again as we would parse command shell arguments it is better to create a shell application. We would read and write files, therefore include `ShellLib` to the `LibraryClasses`:
+`UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf`:
+```
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = UpdateDmpstoreDump
+  FILE_GUID                      = d14fe21b-7dbf-40ff-96cb-5d6f5b63cda6
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib
+
+[Sources]
+  UpdateDmpstoreDump.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  ShellPkg/ShellPkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+  ShellLib
+```
+
+In the `UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c` we start from reading dump file name from the command argument and opening the file with read and write attributes:
+```
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/ShellLib.h>
+#include <Library/MemoryAllocationLib.h>
+
+VOID Usage()
+{
+  Print(L"Recalculate CRCs for dmpstore command dump\n");
+  Print(L"\n");
+  Print(L"  UpdateDmpstoreDump <filename>\n");
+}
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  if (Argc!=2) {
+    Usage();
+    return EFI_INVALID_PARAMETER;
+  }
+
+  SHELL_FILE_HANDLE FileHandle;
+
+  CHAR16* Filename = Argv[1];
+  EFI_STATUS Status = ShellOpenFileByName(
+    Filename,
+    &FileHandle,
+    EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ,
+    0
+  );
+  if (EFI_ERROR(Status)) {
+    Print(L"Error! Can't open file %s\n", Filename);
+    return Status;
+  }
+
+  ...
+
+  Status = ShellCloseFile(&FileHandle);
+  if (EFI_ERROR(Status)) {
+    Print(L"Can't close file: %r\n", Status);
+  }
+
+  return EFI_SUCCESS;
+}
+```
+
+The dump file can have many records in itself and the size of a record is not a constant, but depends on the record fields. Therefore the only way to fix all record CRCs is to step throught the file records until the file end:
+```
+  UINT64 FileSize;
+  Status = ShellGetFileSize(FileHandle, &FileSize);
+  if (EFI_ERROR(Status)) {
+    Status = ShellCloseFile(&FileHandle);
+    return SHELL_DEVICE_ERROR;
+  }
+
+  UINT64 FilePos = 0;
+  while (FilePos < FileSize) {
+    ...
+  }
+```
+
+Here is a code to read record data and calculate its CRC32. It is pretty similar to the one that `dmpstore` command has it its `LoadVariablesFromFilefunction` (https://github.com/tianocore/edk2/blob/master/ShellPkg/Library/UefiShellDebug1CommandsLib/DmpStore.c):
+```
+UINTN ToReadSize;
+UINT32 NameSize;
+ToReadSize = sizeof(NameSize);
+Status = ShellReadFile(FileHandle, &ToReadSize, &NameSize);
+if (EFI_ERROR(Status) || (ToReadSize != sizeof(NameSize))) {
+  Status = SHELL_VOLUME_CORRUPTED;
+  break;
+}
+FilePos += ToReadSize;
+
+UINT32 DataSize;
+ToReadSize = sizeof(DataSize);
+Status = ShellReadFile(FileHandle, &ToReadSize, &DataSize);
+if (EFI_ERROR(Status) || (ToReadSize != sizeof(DataSize))) {
+  Status = SHELL_VOLUME_CORRUPTED;
+  break;
+}
+FilePos += ToReadSize;
+
+UINTN RemainingSize = NameSize +
+                      sizeof(EFI_GUID) +
+                      sizeof(UINT32) +
+                      DataSize;
+UINT8* Buffer = AllocatePool(sizeof(NameSize) + sizeof(DataSize) + RemainingSize);
+if (Buffer == NULL) {
+  Status = SHELL_OUT_OF_RESOURCES;
+  break;
+}
+
+*(UINT32*)Buffer = NameSize;
+*((UINT32*)Buffer + 1) = DataSize;
+
+ToReadSize = RemainingSize;
+Status = ShellReadFile(FileHandle, &ToReadSize, (UINT32*)Buffer + 2);
+if (EFI_ERROR(Status) || (ToReadSize != RemainingSize)) {
+  Status = SHELL_VOLUME_CORRUPTED;
+  FreePool (Buffer);
+  break;
+}
+FilePos += ToReadSize;
+
+
+UINT32 Crc32;
+gBS->CalculateCrc32 (
+   Buffer,
+   sizeof(NameSize) + sizeof(DataSize) + RemainingSize,
+   &Crc32
+);
+
+...
+
+FreePool(Buffer);
+```
+
+To calculate the CRC32 checksum here we use `EFI_BOOT_SERVICES.CalculateCrc32()` function:
+```
+EFI_BOOT_SERVICES.CalculateCrc32()
+
+Summary:
+Computes and returns a 32-bit CRC for a data buffer.
+
+Prototype:
+typedef
+EFI_STATUS
+(EFIAPI *EFI_CALCULATE_CRC32)
+ IN VOID *Data,
+ IN UINTN DataSize,
+ OUT UINT32 *Crc32
+ );
+
+Parameters:
+Data 		A pointer to the buffer on which the 32-bit CRC is to be computed.
+DataSize 	The number of bytes in the buffer Data.
+Crc32 		The 32-bit CRC that was computed for the data buffer specified by Data and DataSize.
+
+Description:
+This function computes the 32-bit CRC for the data buffer specified by Data and DataSize. If the 32-bit CRC is computed, then it is returned in Crc32 and EFI_SUCCESS is returned.
+```
+
+When we have our CRC32 checksum we can update file content with a help of a `ShellWriteFile` function:
+```
+UINTN ToWriteSize = sizeof(Crc32);
+Status = ShellWriteFile(
+  FileHandle,
+  &ToWriteSize,
+  &Crc32
+);
+if (EFI_ERROR(Status) || (ToWriteSize != sizeof(Crc32))) {
+  Print(L"Error! Not all data was written\n");
+  FreePool(Buffer);
+  break;
+}
+FilePos += ToWriteSize;
+```
+
+Build our application and use it on the `dmpstore` dump:
+```
+FS0:\> UpdateDmpstoreDump.efi BootOrder.bin
+```
+
+If you look at the file content again you would see that the CRC field has changed.
+
+![hexedit_3.png](hexedit_3.png?raw=true "hexedit after CRC modification")
+
+Now `dmpstore -l` would finish without errors:
+```
+FS0:\> dmpstore -l BootOrder.bin
+Load and set variables from file: BootOrder.bin.
+Variable NV+RT+BS '8BE4DF61-93CA-11D2-AA0D-00E098032B8C:BootOrder' DataSize = 0x08
+```
+
+You can see that variable content was modified:
+```
+FS0:\> dmpstore BootOrder
+Variable NV+RT+BS 'EFIGlobalVariable:BootOrder' DataSize = 0x08
+  00000000: 01 00 00 00 02 00 03 00-                         *........*
+```
+
+You can also use our `ShowBootVariables.efi` application to see the changes:
+```
+FS0:\> ShowBootVariables.efi
+Boot0001
+UEFI QEMU DVD-ROM QM00003
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+
+Boot0000
+UiApp
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
+
+Boot0002*
+EFI Internal Shell
+Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(7C04A583-9E3E-4F1C-AD65-E05268D0B4D1)
+
+Boot0003
+UEFI QEMU HARDDISK QM00001
+PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
+```
+__________________________
+
+We can also verify that our program works in case when there are multiple variables in the dump file.
+
+Just in case you have some persistent variables from the previous lesson delete all the variables under our GUID with a `dmpstore -d -guid <GUID>` command:
+```
+FS0:\> dmpstore -d -guid bb2a829f-7943-4691-a03a-f1f48519d7e6
+dmpstore: No matching variables found. Guid 7C04A583-9E3E-4F1C-AD65-E05268D0B4D1
+
+```
+
+Create new variables and save them to a file:
+```
+FS0:\> SetVariableExample.efi HelloVar nb "Hello World"
+Variable HelloVar was successfully changed
+FS0:\> SetVariableExample.efi ByeVar nbr "Bye World"
+Variable ByeVar was successfully changed
+FS0:\> dmpstore -guid bb2a829f-7943-4691-a03a-f1f48519d7e6 -s MyVar.bin
+Save variable to file: MyVar.bin.
+Variable NV+RT+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:ByeVar' DataSize = 0x16
+Variable NV+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:HelloVar' DataSize = 0x1A
+```
+
+Use hexedit to modify `World` string in both records of a dump file. Here I've just increased each letter code with 1.
+
+Before:
+```
+00000000 0E 00 00 00 14 00 00 00  42 00 79 00 65 00 56 00  ........B.y.e.V.
+00000010 61 00 72 00 00 00 9F 82  2A BB 43 79 91 46 A0 3A  a.r...??*?Cy?F?:
+00000020 F1 F4 85 19 D7 E6 07 00  00 00 42 00 79 00 65 00  ???.??....B.y.e.
+00000030 20 00 57 00 6F 00 72 00  6C 00 64 00 00 00 EC 24   .W.o.r.l.d...?$
+00000040 78 CD 12 00 00 00 18 00  00 00 48 00 65 00 6C 00  x?........H.e.l.
+00000050 6C 00 6F 00 56 00 61 00  72 00 00 00 9F 82 2A BB  l.o.V.a.r...??*?
+00000060 43 79 91 46 A0 3A F1 F4  85 19 D7 E6 03 00 00 00  Cy?F?:???.??....
+00000070 48 00 65 00 6C 00 6C 00  6F 00 20 00 57 00 6F 00  H.e.l.l.o. .W.o.
+00000080 72 00 6C 00 64 00 00 00  97 82 10 13              r.l.d...??..
+```
+After:
+```
+00000000 0E 00 00 00 14 00 00 00  42 00 79 00 65 00 56 00  ........B.y.e.V.
+00000010 61 00 72 00 00 00 9F 82  2A BB 43 79 91 46 A0 3A  a.r...??*?Cy?F?:
+00000020 F1 F4 85 19 D7 E6 07 00  00 00 42 00 79 00 65 00  ???.??....B.y.e.
+00000030 20 00 58 00 70 00 73 00  6D 00 65 00 00 00 EC 24   .X.p.s.m.e...?$
+00000040 78 CD 12 00 00 00 18 00  00 00 48 00 65 00 6C 00  x?........H.e.l.
+00000050 6C 00 6F 00 56 00 61 00  72 00 00 00 9F 82 2A BB  l.o.V.a.r...??*?
+00000060 43 79 91 46 A0 3A F1 F4  85 19 D7 E6 03 00 00 00  Cy?F?:???.??....
+00000070 48 00 65 00 6C 00 6C 00  6F 00 20 00 58 00 70 00  H.e.l.l.o. .X.p.
+00000080 73 00 6D 00 65 00 00 00  97 82 10 13              s.m.e...??..
+```
+
+Use our program to update checksums:
+```
+FS0:\> UpdateDmpstoreDump.efi MyVar.bin
+```
+
+Now you can verify that our new dump indeed have changed both variables content:
+```
+FS0:\> dmpstore -guid bb2a829f-7943-4691-a03a-f1f48519d7e6
+Variable NV+RT+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:ByeVar' DataSize = 0x14
+  00000000: 42 00 79 00 65 00 20 00-57 00 6F 00 72 00 6C 00  *B.y.e. .W.o.r.l.*
+  00000010: 64 00 00 00                                      *d...*
+Variable NV+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:HelloVar' DataSize = 0x18
+  00000000: 48 00 65 00 6C 00 6C 00-6F 00 20 00 57 00 6F 00  *H.e.l.l.o. .W.o.*
+  00000010: 72 00 6C 00 64 00 00 00-                         *r.l.d...*
+
+FS0:\> dmpstore -guid bb2a829f-7943-4691-a03a-f1f48519d7e6 -l MyVar.bin
+Load and set variables from file: MyVar.bin.
+Variable NV+RT+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:ByeVar' DataSize = 0x14
+Variable NV+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:HelloVar' DataSize = 0x18
+
+FS0:\> dmpstore -guid bb2a829f-7943-4691-a03a-f1f48519d7e6
+Variable NV+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:HelloVar' DataSize = 0x18
+  00000000: 48 00 65 00 6C 00 6C 00-6F 00 20 00 58 00 70 00  *H.e.l.l.o. .X.p.*
+  00000010: 73 00 6D 00 65 00 00 00-                         *s.m.e...*
+Variable NV+RT+BS 'BB2A829F-7943-4691-A03A-F1F48519D7E6:ByeVar' DataSize = 0x14
+  00000000: 42 00 79 00 65 00 20 00-58 00 70 00 73 00 6D 00  *B.y.e. .X.p.s.m.*
+  00000010: 65 00 00 00                                      *e...*
+```
+
+Keep in mind that if you change size of the variable data, you need to change the `UINT32 DataSize` field as well.
diff --git a/Lessons/Lesson_61/UefiLessonsPkg/UefiLessonsPkg.dsc b/Lessons/Lesson_61/UefiLessonsPkg/UefiLessonsPkg.dsc
new file mode 100644
index 0000000..2180620
--- /dev/null
+++ b/Lessons/Lesson_61/UefiLessonsPkg/UefiLessonsPkg.dsc
@@ -0,0 +1,84 @@
+##
+# Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
+#
+# SPDX-License-Identifier: MIT
+##
+
+[Defines]
+  DSC_SPECIFICATION              = 0x0001001C
+  PLATFORM_GUID                  = 3db7270f-ffac-4139-90a4-0ae68f3f8167
+  PLATFORM_VERSION               = 0.01
+  PLATFORM_NAME                  = UefiLessonsPkg
+  SKUID_IDENTIFIER               = DEFAULT
+  SUPPORTED_ARCHITECTURES        = X64
+  BUILD_TARGETS                  = RELEASE
+
+
+[LibraryClasses]
+  UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
+  UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
+  DebugLib|MdePkg/Library/UefiDebugLibConOut/UefiDebugLibConOut.inf
+  BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
+  #PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
+  PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
+  BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
+  RegisterFilterLib|MdePkg/Library/RegisterFilterLibNull/RegisterFilterLibNull.inf
+  PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
+  DebugPrintErrorLevelLib|MdePkg/Library/BaseDebugPrintErrorLevelLib/BaseDebugPrintErrorLevelLib.inf
+  UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
+  MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
+  DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
+  UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
+  ShellCEntryLib|ShellPkg/Library/UefiShellCEntryLib/UefiShellCEntryLib.inf
+  ShellLib|ShellPkg/Library/UefiShellLib/UefiShellLib.inf
+  FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf  
+  HiiLib|MdeModulePkg/Library/UefiHiiLib/UefiHiiLib.inf
+  SortLib|MdeModulePkg/Library/UefiSortLib/UefiSortLib.inf
+  UefiHiiServicesLib|MdeModulePkg/Library/UefiHiiServicesLib/UefiHiiServicesLib.inf
+  UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
+  #SimpleLibrary|UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
+  #SimpleLibrary|UefiLessonsPkg/Library/SimpleLibraryWithConstructor/SimpleLibraryWithConstructor.inf
+  SimpleLibrary|UefiLessonsPkg/Library/SimpleLibraryWithConstructorAndDestructor/SimpleLibraryWithConstructorAndDestructor.inf
+
+[Components]
+  UefiLessonsPkg/SimplestApp/SimplestApp.inf
+  UefiLessonsPkg/HelloWorld/HelloWorld.inf
+  UefiLessonsPkg/ImageHandle/ImageHandle.inf
+  UefiLessonsPkg/ImageInfo/ImageInfo.inf
+  UefiLessonsPkg/MemoryInfo/MemoryInfo.inf
+  UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf
+  UefiLessonsPkg/ListVariables/ListVariables.inf
+  UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf
+  UefiLessonsPkg/InteractiveApp/InteractiveApp.inf
+  UefiLessonsPkg/PCDLesson/PCDLesson.inf
+  UefiLessonsPkg/SmbiosInfo/SmbiosInfo.inf
+  UefiLessonsPkg/ShowTables/ShowTables.inf
+  UefiLessonsPkg/AcpiInfo/AcpiInfo.inf
+  UefiLessonsPkg/SaveBGRT/SaveBGRT.inf
+  UefiLessonsPkg/ListPCI/ListPCI.inf
+  UefiLessonsPkg/SimpleDriver/SimpleDriver.inf
+  UefiLessonsPkg/PCIRomInfo/PCIRomInfo.inf
+  UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
+  UefiLessonsPkg/Library/SimpleLibraryWithConstructor/SimpleLibraryWithConstructor.inf
+  UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
+  UefiLessonsPkg/SimpleClassProtocol/SimpleClassProtocol.inf
+  UefiLessonsPkg/SimpleClassUser/SimpleClassUser.inf
+  UefiLessonsPkg/HotKeyDriver/HotKeyDriver.inf
+  UefiLessonsPkg/ShowHII/ShowHII.inf
+  UefiLessonsPkg/HIIStringsC/HIIStringsC.inf
+  UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.inf
+  UefiLessonsPkg/HIIStringsUNIRC/HIIStringsUNIRC.inf
+  UefiLessonsPkg/HIIStringsMan/HIIStringsMan.inf
+  UefiLessonsPkg/HIIAddRussianFont/HIIAddRussianFont.inf
+  UefiLessonsPkg/HIIAddLocalization/HIIAddLocalization.inf
+  UefiLessonsPkg/AddNewLanguage/AddNewLanguage.inf
+  UefiLessonsPkg/HIISimpleForm/HIISimpleForm.inf
+  UefiLessonsPkg/HIIStaticForm/HIIStaticForm.inf
+  UefiLessonsPkg/HIIStaticFormDriver/HIIStaticFormDriver.inf
+  UefiLessonsPkg/DisplayHIIByGuid/DisplayHIIByGuid.inf
+  UefiLessonsPkg/SetVariableExample/SetVariableExample.inf
+  UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
+
+[PcdsFixedAtBuild]
+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32_2|44
+
diff --git a/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c b/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c
new file mode 100644
index 0000000..e926514
--- /dev/null
+++ b/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/ShellLib.h>
+#include <Library/MemoryAllocationLib.h>
+
+VOID Usage()
+{
+  Print(L"Recalculate CRCs for dmpstore command dump\n");
+  Print(L"\n");
+  Print(L"  UpdateDmpstoreDump <filename>\n");
+}
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  if (Argc!=2) {
+    Usage();
+    return EFI_INVALID_PARAMETER;
+  }
+
+  SHELL_FILE_HANDLE FileHandle;
+
+  CHAR16* Filename = Argv[1];
+  EFI_STATUS Status = ShellOpenFileByName(
+    Filename,
+    &FileHandle,
+    EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ,
+    0
+  );
+  if (EFI_ERROR(Status)) {
+    Print(L"Error! Can't open file %s\n", Filename);
+    return Status;
+  }
+
+  UINT64 FileSize;
+  Status = ShellGetFileSize(FileHandle, &FileSize);
+  if (EFI_ERROR(Status)) {
+    Status = ShellCloseFile(&FileHandle);
+    return SHELL_DEVICE_ERROR;
+  }
+
+  UINT64 FilePos = 0;
+  while (FilePos < FileSize) {
+    UINTN ToReadSize;
+    UINT32 NameSize;
+    ToReadSize = sizeof(NameSize);
+    Status = ShellReadFile(FileHandle, &ToReadSize, &NameSize);
+    if (EFI_ERROR(Status) || (ToReadSize != sizeof(NameSize))) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      break;
+    }
+    FilePos += ToReadSize;
+
+    UINT32 DataSize;
+    ToReadSize = sizeof(DataSize);
+    Status = ShellReadFile(FileHandle, &ToReadSize, &DataSize);
+    if (EFI_ERROR(Status) || (ToReadSize != sizeof(DataSize))) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      break;
+    }
+    FilePos += ToReadSize;
+    
+    UINTN RemainingSize = NameSize +
+                          sizeof(EFI_GUID) +
+                          sizeof(UINT32) +
+                          DataSize;
+    UINT8* Buffer = AllocatePool(sizeof(NameSize) + sizeof(DataSize) + RemainingSize);
+    if (Buffer == NULL) {
+      Status = SHELL_OUT_OF_RESOURCES;
+      break;
+    }
+
+    *(UINT32*)Buffer = NameSize;
+    *((UINT32*)Buffer + 1) = DataSize;
+    
+    ToReadSize = RemainingSize;
+    Status = ShellReadFile(FileHandle, &ToReadSize, (UINT32*)Buffer + 2);
+    if (EFI_ERROR(Status) || (ToReadSize != RemainingSize)) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      FreePool (Buffer);
+      break;
+    }
+    FilePos += ToReadSize;
+    
+    
+    UINT32 Crc32;
+    gBS->CalculateCrc32 (
+       Buffer,
+       sizeof(NameSize) + sizeof(DataSize) + RemainingSize,
+       &Crc32
+    );
+
+    UINTN ToWriteSize = sizeof(Crc32);
+    Status = ShellWriteFile(
+      FileHandle,
+      &ToWriteSize,
+      &Crc32
+    );
+    if (EFI_ERROR(Status) || (ToWriteSize != sizeof(Crc32))) {
+      Print(L"Error! Not all data was written\n");
+      FreePool(Buffer);
+      break;
+    }
+    FilePos += ToWriteSize;
+    FreePool(Buffer);
+  }
+
+  if (EFI_ERROR(Status)) {
+    Print(L"Error! %r\n", Status);
+  }
+
+  Status = ShellCloseFile(&FileHandle);
+  if (EFI_ERROR(Status)) {
+    Print(L"Can't close file: %r\n", Status);
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf b/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
new file mode 100644
index 0000000..eef23cc
--- /dev/null
+++ b/Lessons/Lesson_61/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
@@ -0,0 +1,26 @@
+##
+# Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
+#
+# SPDX-License-Identifier: MIT
+##
+
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = UpdateDmpstoreDump
+  FILE_GUID                      = d14fe21b-7dbf-40ff-96cb-5d6f5b63cda6
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib 
+
+[Sources]
+  UpdateDmpstoreDump.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  ShellPkg/ShellPkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+  ShellLib
diff --git a/Lessons/Lesson_61/bootorder.png b/Lessons/Lesson_61/bootorder.png
new file mode 100644
index 0000000..242d2b5
--- /dev/null
+++ b/Lessons/Lesson_61/bootorder.png
diff --git a/Lessons/Lesson_61/hexedit_1.png b/Lessons/Lesson_61/hexedit_1.png
new file mode 100644
index 0000000..95d8def
--- /dev/null
+++ b/Lessons/Lesson_61/hexedit_1.png
diff --git a/Lessons/Lesson_61/hexedit_2.png b/Lessons/Lesson_61/hexedit_2.png
new file mode 100644
index 0000000..2048428
--- /dev/null
+++ b/Lessons/Lesson_61/hexedit_2.png
diff --git a/Lessons/Lesson_61/hexedit_3.png b/Lessons/Lesson_61/hexedit_3.png
new file mode 100644
index 0000000..b5204ae
--- /dev/null
+++ b/Lessons/Lesson_61/hexedit_3.png
diff --git a/Lessons/Lesson_61/hexedit_help.png b/Lessons/Lesson_61/hexedit_help.png
new file mode 100644
index 0000000..fc04e4c
--- /dev/null
+++ b/Lessons/Lesson_61/hexedit_help.png
diff --git a/README.md b/README.md
index 4291b62..8f8a623 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,7 @@ These series of lessons are intendend to get you started with UEFI programming i
 - [Lesson 58](Lessons/Lesson_58): `subtitle` and `text` VFR elements
 - [Lesson 59](Lessons/Lesson_59): Create an application to display HII Forms by package list GUIDs. Convert our simple form application to UEFI driver form
 - [Lesson 60](Lessons/Lesson_60): Use `gRT->SetVariable()` function to create and delete UEFI variables. Investigate variable attributes. Practical uses of the `dmpstore` command
+- [Lesson 61](Lessons/Lesson_61): Use `dmpstore` command to save/load variables to/from files. Write an application to recalculate CRC32 checksums in the `dmpstore` variable dumps
 
 
 _____
diff --git a/UefiLessonsPkg/UefiLessonsPkg.dsc b/UefiLessonsPkg/UefiLessonsPkg.dsc
index b33c87d..2180620 100644
--- a/UefiLessonsPkg/UefiLessonsPkg.dsc
+++ b/UefiLessonsPkg/UefiLessonsPkg.dsc
@@ -77,6 +77,7 @@
   UefiLessonsPkg/HIIStaticFormDriver/HIIStaticFormDriver.inf
   UefiLessonsPkg/DisplayHIIByGuid/DisplayHIIByGuid.inf
   UefiLessonsPkg/SetVariableExample/SetVariableExample.inf
+  UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
 
 [PcdsFixedAtBuild]
   gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32_2|44
diff --git a/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c b/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c
new file mode 100644
index 0000000..e926514
--- /dev/null
+++ b/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/ShellLib.h>
+#include <Library/MemoryAllocationLib.h>
+
+VOID Usage()
+{
+  Print(L"Recalculate CRCs for dmpstore command dump\n");
+  Print(L"\n");
+  Print(L"  UpdateDmpstoreDump <filename>\n");
+}
+
+INTN EFIAPI ShellAppMain(IN UINTN Argc, IN CHAR16 **Argv)
+{
+  if (Argc!=2) {
+    Usage();
+    return EFI_INVALID_PARAMETER;
+  }
+
+  SHELL_FILE_HANDLE FileHandle;
+
+  CHAR16* Filename = Argv[1];
+  EFI_STATUS Status = ShellOpenFileByName(
+    Filename,
+    &FileHandle,
+    EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ,
+    0
+  );
+  if (EFI_ERROR(Status)) {
+    Print(L"Error! Can't open file %s\n", Filename);
+    return Status;
+  }
+
+  UINT64 FileSize;
+  Status = ShellGetFileSize(FileHandle, &FileSize);
+  if (EFI_ERROR(Status)) {
+    Status = ShellCloseFile(&FileHandle);
+    return SHELL_DEVICE_ERROR;
+  }
+
+  UINT64 FilePos = 0;
+  while (FilePos < FileSize) {
+    UINTN ToReadSize;
+    UINT32 NameSize;
+    ToReadSize = sizeof(NameSize);
+    Status = ShellReadFile(FileHandle, &ToReadSize, &NameSize);
+    if (EFI_ERROR(Status) || (ToReadSize != sizeof(NameSize))) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      break;
+    }
+    FilePos += ToReadSize;
+
+    UINT32 DataSize;
+    ToReadSize = sizeof(DataSize);
+    Status = ShellReadFile(FileHandle, &ToReadSize, &DataSize);
+    if (EFI_ERROR(Status) || (ToReadSize != sizeof(DataSize))) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      break;
+    }
+    FilePos += ToReadSize;
+    
+    UINTN RemainingSize = NameSize +
+                          sizeof(EFI_GUID) +
+                          sizeof(UINT32) +
+                          DataSize;
+    UINT8* Buffer = AllocatePool(sizeof(NameSize) + sizeof(DataSize) + RemainingSize);
+    if (Buffer == NULL) {
+      Status = SHELL_OUT_OF_RESOURCES;
+      break;
+    }
+
+    *(UINT32*)Buffer = NameSize;
+    *((UINT32*)Buffer + 1) = DataSize;
+    
+    ToReadSize = RemainingSize;
+    Status = ShellReadFile(FileHandle, &ToReadSize, (UINT32*)Buffer + 2);
+    if (EFI_ERROR(Status) || (ToReadSize != RemainingSize)) {
+      Status = SHELL_VOLUME_CORRUPTED;
+      FreePool (Buffer);
+      break;
+    }
+    FilePos += ToReadSize;
+    
+    
+    UINT32 Crc32;
+    gBS->CalculateCrc32 (
+       Buffer,
+       sizeof(NameSize) + sizeof(DataSize) + RemainingSize,
+       &Crc32
+    );
+
+    UINTN ToWriteSize = sizeof(Crc32);
+    Status = ShellWriteFile(
+      FileHandle,
+      &ToWriteSize,
+      &Crc32
+    );
+    if (EFI_ERROR(Status) || (ToWriteSize != sizeof(Crc32))) {
+      Print(L"Error! Not all data was written\n");
+      FreePool(Buffer);
+      break;
+    }
+    FilePos += ToWriteSize;
+    FreePool(Buffer);
+  }
+
+  if (EFI_ERROR(Status)) {
+    Print(L"Error! %r\n", Status);
+  }
+
+  Status = ShellCloseFile(&FileHandle);
+  if (EFI_ERROR(Status)) {
+    Print(L"Can't close file: %r\n", Status);
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf b/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
new file mode 100644
index 0000000..eef23cc
--- /dev/null
+++ b/UefiLessonsPkg/UpdateDmpstoreDump/UpdateDmpstoreDump.inf
@@ -0,0 +1,26 @@
+##
+# Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
+#
+# SPDX-License-Identifier: MIT
+##
+
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = UpdateDmpstoreDump
+  FILE_GUID                      = d14fe21b-7dbf-40ff-96cb-5d6f5b63cda6
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = ShellCEntryLib 
+
+[Sources]
+  UpdateDmpstoreDump.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  ShellPkg/ShellPkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  ShellCEntryLib
+  ShellLib