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corna / me_cleaner

Tool for partial deblobbing of Intel ME/TXE firmware images
GNU General Public License v3.0
4.46k stars 277 forks source link

Finally a way to firmware-kill ME discovered by some accident! #215

Open WaseemAlkurdi opened 6 years ago

WaseemAlkurdi commented 6 years ago

Dear @corna and all interested, I have been tinkering as usual on my laptop, an HP EliteBook Revolve 810 G2 (i5-4300u w/ vPro), with BIOS version L86 01.40. I keep a macOS / Linux dual-boot on it. Yesterday, after rebooting from macOS, a strange red error message '''ME State Recovery Mode''' appeared in red letters on the top-left corner of the screen. The system boots normally though. In the ESC startup menu, the options to enter Intel ME setup (F5) and Initiate Intel CIRA (F6) vanished. However, the Intel ME options in the EFI firmware (BIOS) setup menu remained present (but have no effect). I can't enter the MEBx panel. Doing # ./mei-amt-check results in:

Error: Management Engine refused connection. This probably means you don't have AMT

instead of the usual output. Also, checking my /sys/firmware/efi/efivars under Linux, I found this new variable:

VPROState-a82471a8-e491-42c1-9240-4fde3073c0fd

Attempting to cat it results in a weird character, and opening it w/ nano shows a ^A.

This problem is in itself known to HP and the solution is to reflash. But we don't want to re-enable ME. We want to preserve then reverse engineer the change that happened so we can do it anytime. Isn't that a possible kill-switch for ME? I have no Windows installation, but I will install Windows if needed. Anything I can help with?

forkoz commented 6 years ago

Dump full flash and post it up.

WaseemAlkurdi commented 6 years ago

@forkoz As in "dump the BIOS chip with a hardware programmer", right?

xCuri0 commented 6 years ago

@WaseemAlkurdi yes

FrostKnight commented 5 years ago

@EaseemAlkirdi, please document it especially for processors that intel has abandoned, especially gen 3 and gen 4