Recently I got lots of questions for writing UEFI variables (ALT =), I believe it is because users wants to unlock the capability of your system. And some blogs even mentioned how to do it with RU.
Due to the security reason, recent UEFI system firmware will not allow you to modify sensitive settings (variables). And there is no way to change it unless you can update the SPI by a physical programmer.
Here are what error numbers mean (UEFI spec) after you pressed CTRL-W.
0x00000000 EFI_SUCCESS
0x00000001 EFI_LOAD_ERROR
0x00000002 EFI_INVALID_PARAMETER
0x00000003 EFI_UNSUPPORTED
0x00000004 EFI_BAD_BUFFER_SIZE
0x00000005 EFI_BUFFER_TOO_SMALL
0x00000006 EFI_NOT_READY
0x00000007 EFI_DEVICE_ERROR
0x00000008 EFI_WRITE_PROTECTED
0x00000009 EFI_OUT_OF_RESOURCES
0x0000000a EFI_VOLUME_CORRUPTED
0x0000000b EFI_VOLUME_FULL
0x0000000c EFI_NO_MEDIA
0x0000000d EFI_MEDIA_CHANGED
0x0000000e EFI_NOT_FOUND
0x0000000f EFI_ACCESS_DENIED
0x00000010 EFI_NO_RESPONSE
0x00000011 EFI_NO_MAPPING
0x00000012 EFI_TIMEOUT
0x00000013 EFI_NOT_STARTED
0x00000014 EFI_ALREADY_STARTED
0x00000015 EFI_ABORTED
0x00000016 EFI_ICMP_ERROR
0x00000017 EFI_TFTP_ERROR
0x00000018 EFI_PROTOCOL_ERROR
0x00000019 EFI_INCOMPATIBLE_VERSION
0x0000001a EFI_SECURITY_VIOLATION
0x0000001b EFI_CRC_ERROR
0x0000001c EFI_END_OF_MEDIA
0x0000001f EFI_END_OF_FILE
0x00000020 EFI_INVALID_LANGUAGE
0x00000021 EFI_COMPROMISED_DATA
0x00000023 EFI_HTTP_ERROR
I won't be able to provide you on how to make it working, it is what it is from RU's perspective.
