[coreboot] Lenovo T60 Type 8743-GZU - RAM Support? 3Gb or 4Gb

[Peter Stuge]

Josh Stump wrote:
> I have a Lenovo T60 Type 8743-GZU.  From experience I know that with the
> stock BIOS if I put in 4Gb of RAM I can only utilze 3Gb even with a 64bit
> OS installed.  Is this a limitation of the stock BIOS that coreboot can
> overcome or is this simply a chipset limitation and even if I got coreboot
> flashed I still would only have use of 4Gb of RAM.  Does anyone know for
> certain?

It is a limitation of the factory BIOS. For comparison, on an X60
with 4GB of RAM with coreboot there is immediately 3.2GB available
for OS use.

This is with the standard resource allocator in coreboot, ie. without
any intense optimizations. If you work on optimizing this, you may
get even more usable RAM.

The technical limit is that many of the hardware parts in the system
require that they be memory mapped into the CPU bus, and that is only
32 bits, so some of the 4GB of RAM will be "covered" by these
hardware memory regions, but with coreboot you have an opportunity to
work on reducing this to the bare minimum.


> what parts I might need to flash my rom over.

You need the flashrom source, a small patch, and my bucts utility
from http://git.stuge.se/?p=bucts.git

Patch flashrom to use RES1 SPI identification and spi_chip_write1 for
your flash chip, as well as change the flash chip model id to fit the
RES1 command.

then run flashrom -p internal:laptop=force_I_want_a_brick -r factory.bin
# this step is IMPORTANT since the factory BIOS in your machine is
# tied to your particular system board "planar in IBM FRU terms" with
# a unique ID not present in factory BIOS updates

then build coreboot.rom
# note that you must include the correct VGA BIOS for your machine in
# order to have any graphics working when you use coreboot

then run dd if=coreboot.rom of=top64k.bin bs=1 \
 skip=$[sizeof(coreboot.rom) - 0x10000] count=64k

then run dd if=top64k of=coreboot.rom bs=1 \
 seek=$[sizeof(coreboot.rom) - 0x20000] count=64k conv=notrunc

then run bucts 1

then run flashrom -p internal:laptop=force_I_want_a_brick -w coreboot.rom
# this will be slow, and shall generate an erase error at e.g. 0x1f0000
# when working with a 2 Mbyte flash chip.

then power cycle, now starting with coreboot

then undo the flashrom patch, so that you have a stock flashrom

then run bucts 0

then run flashrom -p internal:laptop=force_I_want_a_brick -w coreboot.rom
# his will successfully overwrite the entire flash chip, including
# the last 64k that were write protected with the factory BIOS.


Many thanks to Sven for figuring out this procedure! It has been
successfully performed on at least two X60 machines with factory
BIOS.


ron minnich wrote:
> It's almost certainly impossible to get coreboot going on your T60.

I believe Sven's port is working!


//Peter