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

Jose Trujillo ce.autom at protonmail.com
Wed Sep 26 09:19:02 CEST 2018

You are welcome,

No, don't change it, you change the size of coreboot only if during the building process "make" complain that there is not enough space but in your case your build was already successful leave it like that.

In the rare circumstance that more space is required you can increase coreboot size to 4MB and istill will fit into your system 5MB of space available.

"ifdtool" will inject coreboot in the top of the BYT_orig.bin and save as BYT_orig.bin.new that you can flash to your system.

Please follow Nico's recommendations and be aware that is highly likely that the system will not boot the first time and you will need an external programmer for restoring the system.

Have a good day,
Jose Trujillo.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, September 25, 2018 11:59 PM, Zvi Vered <veredz72 at gmail.com> wrote:

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