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Diffstat (limited to 'scripts/newbitmaps/HWID.txt')
-rw-r--r-- | scripts/newbitmaps/HWID.txt | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/scripts/newbitmaps/HWID.txt b/scripts/newbitmaps/HWID.txt new file mode 100644 index 00000000..faf9479c --- /dev/null +++ b/scripts/newbitmaps/HWID.txt @@ -0,0 +1,58 @@ + +This describes how to change the HWID string that's displayed using the +new-style BIOS bitmaps. For a more detailed explanation of what's going on, +refer to the README file. + +The HWID is encoded in the GBB in two ways: An ASCII string that userspace +can read from /sys/devices/platform/chromeos_acpi/HWID, and as a rendered +bitmap that shows up on the BIOS screens. + + +Here's how to generate a new bitmap blob with a modified HWID + +1. OUTSIDE the chroot, cd to + src/platform/vboot_reference/scripts/newbitmaps/strings + +2. Edit the file 'hwid.txt' to contain your new string. + +3. Run "./text_to_bmp hwid.txt" to create "hwid.bmp" which contains ONLY the + picture of the HWID string. + +4. Copy the hwid.bmp image to the directory where the rest of the bitmap + blob comes from (which might not be public yet). If you don't know where + that is, just use the example directory: + + src/platform/vboot_reference/scripts/newbitmaps/images/1280x800 + +5. cd to the bitmap source directory, INSIDE the chroot. + +6. Edit the .yaml file that describes the bitmap blob (if you're in the + 1280x800 directory, it's called "unknown.yaml"). Change the line that + starts with "hwid:" to refer to your new hwid.bmp file (or replace the + existing hwid bitmap file with your new one). + +7. Run "bmpblock_utility -c unknown.yaml new_bitmaps.bin", to create the new + bitmap blob. + +8. Install the new_bitmaps.bin on your device (see below). + + + + +The gbb_utility is used to replace both the ASCII string and the bitmap blob +in a BIOS image. The typical proces is to do this as root on the target +system. This will only work if THE BIOS write-protect is disabled. + + +A. Read the existing BIOS from ROM (so you don't lose the VPD): + + cd /mnt/stateful_partition + flashrom -r bios.bin + +B. Modify the GBB in the BIOS image to contain the new bits: + + gbb_utility -s 'NEW HWID STRING 1234' -b new_bitmaps.bin bios.bin + +C. Write the modified BIOS back to ROM: + + flashrom -w bios.bin |