Hi,

The array object in Python 3.9 no longer supports fromstring() and tostring() methods. EDK2 BaseTools use these methods, and therefore the EDK2 build fails when using Python 3.9. See the trace below.

Thanks,
Sergey

build.py...

: error C0DE: Tools code failure

        Please send email to devel@edk2.groups.io for help, attaching following call stack trace!

Traceback (most recent call last):

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\GenFds.py", line 371, in GenFdsApi

    GenFds.GenFd('', FdfParserObj, BuildWorkSpace, ArchList)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\GenFds.py", line 510, in GenFd

    FdObj.GenFd()

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\Fd.py", line 131, in GenFd

    RegionObj.AddToBuffer (FdBuffer, self.BaseAddress, self.BlockSizeList, self.ErasePolarity, GenFdsGlobalVariable.ImageBinDict, self.DefineVarDict, Flag=Flag)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\Region.py", line 134, in AddToBuffer

    FvObj.AddToBuffer(FvBuffer, FvBaseAddress, BlockSize, BlockNum, ErasePolarity, Flag=Flag)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\Fv.py", line 127, in AddToBuffer

    FileName = FfsFile.GenFfs(MacroDict, FvParentAddr=BaseAddress, IsMakefile=Flag, FvName=self.UiFvName)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\FfsFileStatement.py", line 153, in GenFfs

    sectList, align = section.GenSection(OutputDir, self.NameGuid, SecIndex, self.KeyStringList, None, Dict)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\GuidSection.py", line 95, in GenSection

    ReturnSectList, align = Sect.GenSection(OutputPath, ModuleName, SecIndex, KeyStringList, FfsInf, Dict, IsMakefile=IsMakefile)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\FvImageSection.py", line 108, in GenSection

    FvFileName = Fv.AddToBuffer(Buffer, self.FvAddr, MacroDict = Dict, Flag=IsMakefile)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\Fv.py", line 127, in AddToBuffer

    FileName = FfsFile.GenFfs(MacroDict, FvParentAddr=BaseAddress, IsMakefile=Flag, FvName=self.UiFvName)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\FfsFileStatement.py", line 153, in GenFfs

    sectList, align = section.GenSection(OutputDir, self.NameGuid, SecIndex, self.KeyStringList, None, Dict)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\UiSection.py", line 70, in GenSection

    GenFdsGlobalVariable.GenerateSection(OutputFile, None, 'EFI_SECTION_USER_INTERFACE', Ui=NameString, IsMakefile=IsMakefile)

  File "C:\edk2-upx\edk2\BaseTools\Source\Python\GenFds\GenFdsGlobalVariable.py", line 466, in GenerateSection

    SectionData.fromstring(Ui.encode("utf_16_le"))

AttributeError: 'array.array' object has no attribute 'fromstring'