From e6151430c2944368b1b7612e6cee67f95d45f830 Mon Sep 17 00:00:00 2001 From: Leah Rowe Date: Wed, 10 Jan 2024 16:50:03 +0000 Subject: [PATCH] cleanup Signed-off-by: Leah Rowe --- site/docs/hardware/hp820g2.md | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/site/docs/hardware/hp820g2.md b/site/docs/hardware/hp820g2.md index 0aab1e1..03b8d40 100644 --- a/site/docs/hardware/hp820g2.md +++ b/site/docs/hardware/hp820g2.md @@ -58,6 +58,11 @@ P*: Partially works with blobs | **SeaBIOS** | Works | | **SeaBIOS with GRUB** | Works | + +Full hardware specifications can be found on HP's own website: + + + Introduction ============ @@ -244,19 +249,13 @@ This is to prevent short circuiting and power surges while flashing.** For general information, please refer to [25xx NOR flash instructions](../install/spi.md). -At this present time, disassembly instructions are unavailable from the -Libreboot project, but you can search for HP's own hardware maintenance manual -or look at videos online showing disassembly. - -The flash chip is visible by removing the "bottom door" panel. But the -frame makes it hard to put a clip on it, so it's recommended to follow the -HP [service manual](https://h10032.www1.hp.com/ctg/Manual/c03015458.pdf) -to remove the **bottom cover**, as it's called. - +Remove the bottom cover via the latch, and the flashes are accessible. First, dump both flashes for backup, using the `-r` option (instead of `-w`) in flashrom. Two dumps of each flash, make sure both dumps match for each chip. -We will assume that your system flash (16MB) dump is named `dump.bin`. +We will assume that your system flash (16MB) dump is named `dump.bin`. This is +the dump of your 16MB flash, containing HP's firmware, including the final +bootblock and EC firmware. This gives you everything, including the final 4MB. Now insert your new ROM into a copy of `dump.bin`: @@ -270,6 +269,14 @@ Flash `new.bin` to system flash (16MB IC) using the `-w` option in flashrom, and erase the private (2MB) flash IC, using the `--erase` option (instead of `-w filename.rom`) in flashrom. +In the above example, you replaced the first 12MB of the HP dump with that of +your Libreboot image, but leaving the final 4MB intact which contains the EC +firmware. Libreboot's custom IFD sets everything so that all regions, from +IFD to GbE, ME and then BIOS region, exist within the first 12MB of flash. +This makes the machine boot from the end of the 12MB section, containing the +coreboot bootblock, instead of the HP bootblock (which is never executed but +must remain intact). + It's very important that you *erase* the 2MB flash. Be careful *not* to erase the system (16MB flash). This is yet another reason why you should keep a backup of both flash ICs, just in case (dumped using `-r` in flashrom).