Check the integrity of the ME modules

Check the integrity of the ME modules

Before flashing you can check the validity of the modules hashes to reduce the possibility of bricking (Intel ME, pre-Skylake only) using unhuffme. Unfortunately unhuffme segfaults on shrinked ME images, so it's not compatible with the -r option of me_cleaner.

Download the sources from https://io.netgarage.org/me/, build them and run

 $ ./unhuffme <modified image>

It should print the list of the modules in this format:

 <name> <SHA-256 hash> <lzma, [MATCH] or incomplete>

• [MATCH] means that the module is compressed with Huffman, it has been uncompressed and its hash matches with the signed hash in the module manifest.
• incomplete means that the module is compressed with Huffman, it has been uncompressed but its hash DOES NOT match the signed hash in the module manifest.
• lzma means that the module is compressed with standard LZMA and unhuffme ignored it. You can manually compare its hash (with lzcat mod/MODULE_NAME-*.mod.lzma | sha256sum) with the printed one. If lzcat returns File format not recognized it means that this module has been removed.

The fundamental modules (that can't be removed) are BUP and (sometimes missing) ROMP, so you should have [MATCH] (or lzma with a valid hash) for these two modules and incomplete (or lzma with an invalid hash) for any other module.

For example, this is the output of unhuffme on a working deblobbed Intel ME image:

Flash partition table (1 entries):
    partition:  FTPR(type:0) at 000cc000, size:76000

Code partition: FTPR(9 modules, v7.1.86.1221)
	     0           UPDATE     lzma at:   44a32 va:2003d000+2000
	     1              BUP  huffman at:     780 va:20040000+11000
	     2           KERNEL  huffman at:     780 va:20055000+2a000
	     3           POLICY  huffman at:     780 va:2008a000+1c000
	     4         HOSTCOMM     lzma at:   44ac4 va:20515000+b000
	     5              RSA     lzma at:   4a05a va:2052a000+c000
	     6              CLS     lzma at:   4eb17 va:20539000+a000
	     7              TDT     lzma at:   53529 va:2054a000+e000
	     8             FTCS  huffman at:     780 va:200a8000+7000

        UPDATE	13f1e1e6479e383099dcf7bb2db126b55d1d64c2daa082cbe138d433940ec97b lzma
           BUP	dd0b82a1e280ac1bbb14f56234b5b5af12de3cf6dd6f1e1df326648b2b479d06 [MATCH]
        KERNEL	2c53fefe9038ed895fbb888fa718ede75189435da60753818c415bca52118e72 incomplete
        POLICY	b28976e29175efd8c561f106ef7b0927e977efee396e697f6bdaf6d76c00993c incomplete
      HOSTCOMM	da4fda7c3b467810df962e340f2ae97e6dc83fa6d33571dc2ed2fd3c9d03b8aa lzma
           RSA	c3e621148fc07c43dac730dbc29b015f39ad8cb79259d5134d3761d5c3ec5aad lzma
           CLS	e60c649469f97ddf8d2ddb83e0b4371d2f850b719fafa4bdcd611bab339a3b35 lzma
           TDT	4bc3fae01571362208547bf3707eec808d7193c09a5b4e55348ab824c9634c20 lzma
          FTCS	e4b9c72ceefb95a19fbff03f7ae8aea75515a04e81a043fa7c3acc3dd4205322 incomplete