iMicroUpdate

A tool to brick your BIOS less easily. This is an experimental application that is capable of replacing Intel microcodes in BIOS ROM files. It is intended to be a replacement for manual copy & paste in hex editors.

License: MIT

Command examples

Scan file

This command lists all microcodes and gaps that could be found within the specified file.

-scan MYROM.ROM

Extract microcode

Scan the file to know the right offset in the ROM file. Afterwards:

-extract MYROM.ROM -posr 0x23830 -bin old_9110676.BIN

Patch ROM file

This command will modify the ROM file at the given offset by the provided microcode:

-patch MYROM.ROM -posr 0x23830 -bin 9110676.BIN

It is also possible to use another ROM as microcode source:

-patch MYROM.ROM -posr 0x23830 -bin IntelAll.BIN -posb 0x32000

In case the microcode sizes mismatch or no microcode is found in the ROM file (gap?), then consider using -force.

WARNING: Ensure there is enough space else it will overwrite adjacent microcodes!

-patch MYROM.ROM -posr 0x23830 -bin new10676.bin -posb 0x32000 -force

Example:

$ ./iMicroUpdate -patch MYROM.ROM -bin 9110676.BIN -posr 0x23830

	ROM file:   MYROM.ROM
	Microcode:  9110676.BIN

Old vs new microcode:
 CPUID | Pf | Rev | Offset  | Size
-------+----+-----+---------+--------
 10676 | 01 | 60C | 0x23830 | 0x1000
 10676 | 44 | 60F | 0x00000 | 0x1000
Please ENTER to confirm.

DONE. Patched.

Erase microcode

Replace a microcode with a gap. This command is helpful to free space to insert larger microcodes. Consider -erase prior -patch ... -force.

-erase MYROM.ROM -posr 0x23830 -fill 0x00

The gap is usually filled with 0x00 (AMI BIOS).

Features

• Scan, extract and replace microcodes
• Cross-platform application
• Script-friendly return code

See also: CPUMicrocode (microcode collection)

Tested

• AMI BIOS: Filling microcode gaps (0x400 bytes of 0x00)
• AMI BIOS: Altered count of microcodes
  • Example: 3 0xC00+0x800+0xC00 to 1 0x2000
  • Needs use of -force if regions get split
• Phoenix BIOS (`_C00.PEI): Altered count of microcodes
  • Use PhoenixTool (primary for SLIC) to extract & rebuild the *.wph file