6.8 KiB
NOTE (15 October 2023): The util is now called dell-flash-unlock, but it
was previously called e6400-flash-unlock. Links have been updated.
BSD boots and works properly on these machines, but take note:
Nicholas's dell-flash-unlock utility has been ported to OpenBSD, but other BSDs are assumed unsupported for now.
NOTE: Libreboot standardises on flashprog now, as of 27 January 2024, which is a fork of flashrom.
NOTE: BSD is mentioned above, but the only BSD tested for dell-flash-unlock
is OpenBSD, as of 15 October 2023.
Flashing from Linux
MAKE SURE you boot with this Linux kernel parameter: iomem=relaxed - this
disables memory protections, permitting /dev/mem access needed by flashprog.
The flash is memory mapped and flashprog accesses it via /dev/mem.
You can flash Libreboot directly from the vendor (Dell) BIOS, without taking the machine apart. It can be done entirely from Linux. It will probably also work on BSD systems, but it has only been testing on Linux thus far.
NOTE (15 October 2023): The util is now called dell-flash-unlock, but it
was previously called e6400-flash-unlock. Links have been updated.
Check util/dell-flash-unlock in the lbmk.git repository, or in release
archives for Libreboot releases from 20230423 onwards.
Go in there:
cd util/dell-flash-unlock
make
With this program, you can unlock the flash in such a way where everything
is writeable. Information about how to use it is in the README.md file which
is included in that program's directory, or you can read it online here:
https://browse.libreboot.org/lbmk.git/plain/util/dell-flash-unlock/README.md
Literally just run that program, and do what it says. You run it once, shut
down, and then power on the machine. Then run it again to confirm that the
flash is unlocked. The source code is intuitive enough that you can easily get
the gist of it; it's writing some EC commands and changing some chipset config
bits. The EC on this machine is hooked up to the HDA_SDO signal, also known
as the Flash Descriptor Override (FDO), which disables any flash protection by
the IFD. When booted with the FDO set, the original Dell firmware disables all
other BIOS write protections such as SMM BIOS lock bits.
Make sure to make a backup of the original firmware before proceeding to flash; see the instructions below.
When you flash it, you can use this command:
flashprog -p internal -w libreboot.rom
Where libreboot.rom is your E6430 ROM. Make sure it's the right one.
If flashprog complains about multiple flash chips detected, just pick one of
them (doesn't matter which one), with the -C flag as directed; just pick one,
and if it doesn't work, try the next.
When you see flashprog say VERIFIED at the end, that means the flash was
successful. If you don't see that, or you're unsure, please contact the
Libreboot project via IRC.
BACK UP THE FACTORY BIOS
The -w option flashes libreboot.rom. You may consider backing up the
original Dell BIOS first, using the -r option:
flashprog -p internal -r backup.rom
AGAIN: make sure to use -C accordingly, if you need to pick a chip (where
flashprog has detected multiple chip definitions). Just pick one, any of them
will probably work, if not try the next.
Do this while in a flashable state, after the 2nd run of dell-flash-unlock.
Make sure the backup.rom file gets backed up to an external storage media,
not the E6430 itself.
With this method, you can probably flash it within 5 minutes. Again, zero disassembly required!
How to flash externally
Refer to spi.md as a guide for external re-flashing.
The SPI flash chip shares a voltage rail with the chipset, which is not isolated using a diode. As a result, powering the flash chip externally may cause the QM77 chipset to partially power up and drive the SPI pins, which can interfere with programmers such as the Raspberry Pi. See RPi Drive Strength for a workaround.
Have a look online for videos showing how to disassemble, if you wish to externally re-flash.