Tim Crawford a9e791c905 scripts: Allow flashing EC only

As somewhat of a hack, allow flashing only the EC by deleting the
`firmware.rom` file before running `flash.sh`.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

2024-05-20 07:54:21 -06:00

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Flashing firmware

Flashing firmware manually is not recommended for the normal user!

Boot time

The first boot after flashing will take a long time. This is due to coreboot initializing RAM modules for the first time. Once memory training is complete, coreboot will cache this information and subsequent boots will take significantly less time.

coreboot's cbmem tool can be used to verify this. The call to FspMemoryInit() can report 20+ seconds on the first boot, and a few hundred milliseconds on subsequent boots.

UEFI application

This is the default method for flashing firmware (using firmware-update). When used from this repo, it only works with systems running System76 open firmware.

./scripts/flash.sh <model>

By default the script will attempt to flash both the BIOS and the EC. Their respective file can be deleted to skip flashing them.

If the EC is flashed, the system will immediately power off.

Internal programmer

Availability

This method is only possible when firmware is unlocked. Firmware is unlocked by one of two methods:

The EC feature CONFIG_SECURITY is unset/disabled
The EC is unlock for a single boot (via firmware-update or ectool)

The current state can be determined using ectool:

./ec/scripts/ectool.sh security

Lock: This method can't be used
Unlock: This method can be used

flashrom

sudo flashrom -p internal -w build/<model>/firmware.rom

External programmer

Use one of these methods for first-time flashing or flashing a bricked system.

Identifying the BIOS chip

The packaging and protocol can be determined by board_info.txt in coreboot. Pin 1 is sometimes marked by a small dot indent and a white paint mark. The silkscreen may also indicate pin 1.

CH341A USB programmer - slower, but easier to set up

These can be purchased from many places for around 15 USD. Make sure that the one you get has a ROM clip. Here are some examples:

Then you can follow these steps to flash the ROM chip:

Turn off the computer
Unplug the AC adapter
Remove the bottom panel
Attach the clip to the SPI ROM chip
Plug the CH341A into a computer with this repository built
Verify that you can access the ROM chip, replacing <model> with your model:

./scripts/ch341a-dump.sh <model>

Flash the firmware you built, replacing <model> with your model:

./scripts/ch341a-flash.sh <model>

SPI Pi - faster, but harder to set up

SPI Pi is a Raspberry Pi used to flash the SPI ROM. To create a SPI Pi:

Get a Raspberry Pi with Ubuntu LTS
Hook up a SPI clip to the SPI Pi
- The SPI Pi's SPI pinout can be found here: https://pinout.xyz/pinout/spi#
- The pinout of a SPI rom can be found here: https://www.totalphase.com/media/wysiwyg/soic8-pinout.png
- If you need more instructions, you should not be hooking up the SPI clip
Connect the SPI Pi's SPI clip to the SPI ROM, ensuring pin 1 of the clip aligns with pin 1 on the ROM
On the SPI Pi, run the following commands:

sudo apt install flashrom
git clone https://github.com/system76/firmware-open.git firmware