16MB X200 ROMs cause a brick due to wrong IFD (EDIT: 4MB also bricks)

[githubisnonfree]

Hi,

I have a person who came to libreboot IRC earlier. he was using an X200 thinkpad with 16MB SPI flash, and he flashed one of your 16MB ROMs

the system did not boot. black screen. it was bricked. i did some investigating:

I saw this in your 16MB ROMs:

FLREG1 (BIOS):

• BASE = 0x0003
• reserved1 = 0x0
• LIMIT = 0x07ff
• reserved2 = 0x0

See: limit 0x07ff

it should be 0x0fff

Basically:

You have inserted the IFD+GBE image, from ich9gen, but you inserted the one for 8MB SPI flash, into the 16MB ROM. this means that you are telling ich9m the bios region ends after last 8MB, rather than 16MB. yet, the bootblock and cbfs is way further up to the end of the chip

please fix this. no need to recompile the roms, but please issue new roms with the correct ifd image

on those 16MB X200 ROMs, the correct file as generated by ich9gen is:

ich9fdgbe_16m.bin

cheers

PS:

And please test your ROMs

[githubisnonfree]

i'm leah btw. leah rowe of libreboot. i don't normally use github

i have another request:

please don't use the name "libreboot" in your repo. the person who flashed your roms earlier thought you were me, that your repo was an official libreboot repo

please call your project something else

[githubisnonfree]

i did some further digging in your build system; seems you use bincfg, not ich9gen, for ifd/gbe. which is fine, but please make sure for ifd that "limit" in flreg1 is set to 0x0fff instead of 0x07ff, in your 16MB ROMs. you can just patch that at build time in bincfg, when doing the 16MB ROMs

you should probably set component1density aswell (again in ifd). values:

for 4MB flash: value should be 3

for 8MB flash: value should be 4

for 16MB flash: value should be 5

component2density is a Do Not Care because these boards are configured for a single flash IC by default

[githubisnonfree]

Just for kicks, I did some further digging. This time I checked your 4MB ROMs:

in your 4MB ROMs, you use an IFD that sets flreg1 limit 0x07ff. this is wrong. on 4MB it should be: 0x03ff

here's a useful guide:

4MB: flreg1 limit 0x03ff, component1density 3

8MB: flreg1 limit 0x07ff, component1density 4

16MB: flreg1 limit 0x0fff, component1density 5

these numbers are explained here:

https://libreboot.org/docs/install/ich9utils.html

the numbers are 24-bit values, and shifted right 12 bits when stored in ifd. numbers are little endian in ifd. when interpreting them, you shift left 12 bits

(for "limit", you add 1 before shifting left. and subtract 1 after shifting right)

see link. it explains everything. bincfg in coreboot seems to only have spec files for 8MB single flash setup like on X200/T400

please fix your ROMs. at present, only the 8MB ROMs actually work. your 4MB and 16MB ROMs will cause a brick

[githubisnonfree]

just use ich9gen. bincfg is great but ich9gen is really flexible in generating different ifd/gbe images for different configurations, whereas bincfg is just a tool that generates a binary from a human readable format, and you have to manipulate that data yourself

ich9gen actually calculates a lot of stuff properly, and even sets the mac address checksum correctly, when changing the mac address. the style of ich9utils is peculiar for sure, the coding style, but it works well. see:

https://notabug.org/libreboot/ich9utils

and read the guide i linked, for how to use it. you can use that instead of bincfg, and insert the right ifd into the roms