google was useless for me too and my hyper-v vm is running UEFI.
i found out the correct command was as follows:
& 'C:\Program Files (x86)\ImgBurn\ImgBurn.exe' /MODE BUILD /BUILDOUTPUTMODE IMAGEFILE /SRC "C:\ISO\Source\" /DEST "C:\ISO\.iso\test121" /VOLUMELABEL "test121" /VOLUMELABEL_UDF "test121" /START /CLOSE /NOIMAGEDETAILS /ROOTFOLDER YES /PRESERVEFULLPATHNAMES NO /OVERWRITE YES /BUILDINPUTMODE STANDARD /BOOTEMUTYPE 0 /BOOTIMAGE C:\ISO\Source\boot\etfsboot.com /BOOTDEVELOPERID "Microsoft Corporation" /BOOTLOADSEGMENT 07C0 /BOOTSECTORSTOLOAD 8 /FILESYSTEM "UDF"
Never seen "CDBOOT: Cannot boot from CD - Code: 3" before only 5, 4 and 1
Thank you for the quick reply, if you want any information on the automation script or the use of your product feel free to ask.
kind regards Necis Orcus