[coreboot] Burn 2MB coreboot.rom on 8MB flash chip

Zvi Vered veredz72 at gmail.com
Tue Sep 25 22:59:24 CEST 2018

Hi Jose,

Thank you very much for the detail information.
The output of ifdtool in layout.txt is:
00000000:00000fff fd
00300000:007fffff bios
00001000:002fffff me

So the original bios size is 0x500000 = 5MB

You wrote:
 if the size of the original BIOS is bigger or equal than coreboot build
you are good to go ahead.

The original "ROM chip size" in menuconfig is 2MB. Should I change it to
8MB ?

I'm aware my board is not identical to the "Bayley Bay FSP-based CRB"
Should I use another board as reference ?

Best regards,

On Tue, Sep 25, 2018 at 10:16 AM Jose Trujillo <ce.autom at protonmail.com>

> Hello Zvika:
> First get the correct original full 8MB FW from the manufacturer or dump
> it from the board with the command in EFI:
> "ftp -d BYT_orig.bin" and double save it.
> 2.- in coreboot/util/ifdtool do make and sudo make install.
> 3.- in terminal go to the FW directory and do:    "ifdtool BYT_orig.bin -f
> fw_layout.txt"
>       a).- in "fw_layout.txt" you will get the BIOS area size from the
> original FW (just substract).
>       b).- if the size of the original BIOS is bigger or equal than
> coreboot build you are good to go ahead.
> 4.- copy/move "BYT_orig.bin" in the directory which resides the coreboot
> folder (not inside the coreboot folder) and do:
>      ifdtool -i BIOS:./coreboot/build/coreboot.rom CB_baytrail.bin
> 5.- flash it:   "fpt -f CB_baytrail.bin" booting from UEFI.
> If the build was correctly done and followed accurately those steps the
> system should boot.
> Good luck,
> Jose Trujillo.
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Monday, September 24, 2018 10:18 PM, Zvi Vered <veredz72 at gmail.com>
> wrote:
> Hello,
> I have an Intel's ATOM Bay Trail board. The output of "inteltool" is:
> CPU: ID 0x30679, Processor Type 0x0, Family 0x6, Model 0x37, Stepping 0x9
> Northbridge: 8086:0f00 (Bay Trail)
> Southbridge: 8086:0f1c (Bay Trail)
> IGD: 8086:0f31 (unknown)
> In coreboot configuration I selected:
> Mainboard -> Mainboard model -> Bayley Bay FSP-based CRB
> The default ROM chip size is 2MB.
> This is also the size of coreboot.rom created after "make"
> The board has 8MB BIOS flash.
> It's delivered with a BIOS programming utility that runs under EFI shell.
> The original BIOS has 2 versions: rom (5MB) and bin (8MB)
> I tried to burn the 2MB coreboot.rom with the vendor's BIOS utlity.
> I got:
> 3 - Error: ROM file size does not match existing BIOS size.
> Should I convert coreboot.rom to coreboot.bin ? How ?
> If not, how can I program coreboot.rom ?
> Thank you,
> Zvika
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