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| 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:
flashprog -p internal
We believe most/all are 4MB (32Mb) flash sizes. The schematics hint that some boards may have 6MB flash (4MB and 2MB, dual chip), but we've only ever seen 4MB setups in the wild. You can still flash the 4MB image on 6MB setups, if it's encountered, by just leaving the higher 2MB part unflashed, because the flash descriptor (in Libreboot) configures everything so that the BIOS region ends just before the 4MB mark, in flash; the BIOS region is the final region, in the higher part of flash as defined by the descriptor, regardless of whether that is the actual end of the flash.
Libreboot does currently provide 6MB images on this board, for these reasons.
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.
Intel GPU errata
Systems with a 1440 x 900 display panel instead of the more common 1280 x 800 panel will have garbled graphics before the OS boots (i.e. in SeaBIOS or GRUB) in Libreboot 20240504 and earlier. This is fixed in releases after 20240504.
This was caused by libgfxinit calculating PLL divider values for the pixel clock assuming a 96 MHz reference frequency, whereas the E6400 uses a 100 MHz reference frequency. The error is not large enough to affect the lower resolution panels, but is enough to affect the 1440 x 900 panels which use a higher pixel clock.
How to flash internally (no diassembly)
Please read the article:
Internally flash Dell Latitude laptops
Dell's original BIOS/UEFI firmware typically prevents write access, but it has bugs which can be exploited, to enable Libreboot installation very easily. You do not have to disassemble the machine.
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.