Re: [PATCH 4/5] efi_loader: disk: Extend EFI_PARTITION_INFO_PROTOCOL to support MBR

[Jan Kiszka <jan.kiszka@siemens.com>]

On 21.01.26 10:28, Javier Martinez Canillas wrote:
> Jan Kiszka <jan.kiszka@siemens.com> writes:
> 
> Hello Jan,
> 
>> On 20.01.26 14:36, Javier Martinez Canillas wrote:
>>> The EFI_PARTITION_INFO_PROTOCOL provides detailed information about
>>> partitions. The UEFI specification mentions that both GPT and MBR
>>> partition schemes are supported, but the U-Boot implementation only
>>> supports the former.
>>>
>>> This can cause compatibility issues for platforms whose boot ROM only
>>> supports MBR. This change adds support for MBR partition tables to
>>> the protocol, making U-Boot compatible with systems that require a
>>> legacy MBR table.
>>
>> Normally, this is simple to address via hybrid partition tables. I've
>> done that already for two different SoCs (TI AM62 and Altera Cyclone V),
>> and this allows to use all the nifty features of the modern GPT without
>> upsetting the ROM loaders. Do you have a SoC where this does not work?
>>
> 
> Yes, I know that could be worked around by using hybrid partition tables
> but IMO using that could be fragile.

Try it, it's not in my experience. Again, you gain modern GPT partitions
this way, for anything but the boot partition the ROM loader needs.

Jan

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