6.4 KiB
| title | x-toc-enable |
|---|---|
| Flashing the Dell Latitude E6400 | true |
Models with Intel graphics are GM45, and fully supported in Canoeboot with native initialisation; ROM images are available since. The Intel video initialisation is libre, implemented with publicly available source code via libgfxinit, from the coreboot project.
Flash chip size
Use this to find out:
flashrom -p internal
We believe most/all are 4MB (32Mb) flash sizes, but larger ROM images are provided for people who wish to upgrade.
MAC address
The MAC address is part of the ROM image that you're flashing. You can change it at any time, before or after you've flashed Canoeboot; you can also change it in the Dell BIOS, if you really want to. This is for the onboard gigabit ethernet device.
Refer to mac_address.md.
It is recommended that you run nvmutil. See:
The nvmutil software is specifically designed for changing MAC addresses,
and it implements a few more safeguards (e.g. prevents multicast/all-zero
MAC addresses) and features (MAC address randomisation, ability to correct or
intententionally corrupt(disable) GbE sections if you wish, swap GbE parts,
etc). You can also run ich9gen, if you wish:
Intel GPU: libre video initialisation available
Canoeboot uses coreboot's native libgfxinit on this platform, for
variants with Intel graphics.
How to flash internally (no diassembly)
Warning for BSD users
+NOTE: 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. The flashrom software is available on BSD systems. Canoeboot's build
system has itself not yet been ported to the BSDs, but you can use the
flash unlock utility.
NOTE: BSD is mentioned above, but the only BSD tested for dell-flash-unlock
is OpenBSD, as of 15 October 2023.
Flashing from GNU+Linux
MAKE SURE you boot with this GNU+Linux kernel parameter: iomem=relaxed - this
disables memory protections, permitting /dev/mem access needed by flashrom.
The flash is memory mapped and flashrom accesses it via /dev/mem.
You can flash Canoeboot directly from the vendor (Dell) BIOS, without taking the machine apart. It can be done entirely from GNU+Linux. It will probably also work on BSD systems, but it has only been testing on GNU+Linux thus far.
NOTE: 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 cbmk.git repository, or in release
archives for Canoeboot releases from 20231026 onward.
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, and shut
down, and when you do, the system brings itself back up automatically. Then
you run it and flash it unlocked. Then you run it again. 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 GPIO33 signal, sometimes called HDA_DOCK_EN, which sets
the flash descriptor override thus disabling any flash protection by the IFD.
It also bypasses the SMM BIOS lock protection by disabling SMIs, and Dell's
BIOS doesn't set any other type of protection either such as writing to
Protected Range registers.
When you flash it, you can use this command:
flashrom -p internal -w canoeboot.rom
Where canoeboot.rom is your E6400 ROM. Make sure it's the right one.
If flashrom complains about multiple flash chips detected, just pick one of
them (doesn't matter which one). On most Dell machines, the most correct
would probably be this option in flashrom: -c MX25L3205D/MX25L3208D.
So:
flashrom -p internal -w canoeboot.rom -c MX25L3205D/MX25L3208D
When you see flashrom say VERIFIED at the end, that means the flash was
successful. If you don't see that, or you're unsure, please contact the
Canoeboot project via IRC.
BACK UP THE FACTORY BIOS
The -w option flashes canoeboot.rom. You may consider backing up the
original Dell BIOS first, using the -r option:
flashrom -p internal -r backup.rom -c MX25L3205D/MX25L3208D
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 E6400 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 ICH9 southbridge, which is not isolated using a diode. As a result, powering the flash chip externally causes the ICH9 to partially power up and attempt to drive the SPI clock pin low, 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.