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Diffstat (limited to 'Documentation/northbridge')
| -rw-r--r-- | Documentation/northbridge/intel/sandybridge/me_cleaner.md | 66 |
1 files changed, 65 insertions, 1 deletions
diff --git a/Documentation/northbridge/intel/sandybridge/me_cleaner.md b/Documentation/northbridge/intel/sandybridge/me_cleaner.md index 1086e7e09199..b457dcdd3c68 100644 --- a/Documentation/northbridge/intel/sandybridge/me_cleaner.md +++ b/Documentation/northbridge/intel/sandybridge/me_cleaner.md @@ -5,7 +5,7 @@ from the ME firmware partition. In this state the ME errors out and doesn't operate any more. **Using a 'cleaned' ME partition may lead to issues and its use should be -carefully evaulated.** +carefully evaluated.** ## Observations with 'cleaned' ME @@ -18,3 +18,67 @@ carefully evaulated.** Always test with unmodified IFD and ME section before reporting bugs to the coreboot project. + +## Tutorial reducing the Intel ME firmware size + +By default the cleaned ME firmware will still occupy the same space in +the firmware image. It's possible to change the firmware partition layout +and reclaim the space for the use by coreboot. +With the reduced Intel ME firmware the `ifd`, `gbe` and `me` regions require +less than 128 KiB of space in the ROM, which leaves the remaining for the +`bios` region. + +This tutorial will guide you through the steps necessary. + +### 1. Obtain a full ROM + +You need a full and working ROM with a full Intel ME firmware. + +### 2. Running me_cleaner + +You need to run the *me_cleaner* on a full ROM, here called `fulldump.rom`: +The full ROM contains: +* IFD +* fully working Intel ME +* GbE (optional) +* BIOS (any firmware) + +Running the command will generate two new files: +```console +./util/me_cleaner/me_cleaner.py -D patched_desciptor.bin -M stripped_me.bin fulldump.rom -t -r -S +``` + +The generated files are: +* a patched IFD called `patched_desciptor.bin` +* stripped Intel ME called `stripped_me.bin` + +The patched IFD has the *AltMeDisable* bit set and a modified flash layout. + + +*Note:* coreboot allows to select `CONFIG_ME_CLEANER` as part of the +build-process, but that doesn't rework the flash layout, it only removes +files from ME and sets the *AltMeDisable*-bit. + +### 3. Build coreboot + +1. Now include the two new files from the previous step into coreboot's + build system. +2. Make sure to also increase the CBFS size + * 0x7E0000 for a 8MiB ROM + * 0xBE0000 for a 12MiB ROM + * 0xFE0000 for a 16MiB ROM +3. Make sure to **not** enable me_cleaner in Kconfig again as + you have already run it + +### 4. Flashing the ROM + +As you have modified the layout you need to write the **full ROM** to flash +using an [external programmer]. +Make sure to include all partitions into the ROM: +* IFD +* EC (might be unused) +* GbE (might be unused) +* ME +* BIOS + +[external programmer]: ../../../flash_tutorial/index.md |