GPT boot has less features than legacy MBR-based one (Was: UEFI, loader.efi and /boot.config)

[Toomas Soome]

> On 18 Jan 2019, at 19:57, Lev Serebryakov <lev at FreeBSD.org> wrote:
> 
> On 18.01.2019 20:13, Warner Losh wrote:
> 
>>> Also, there are same problems with GPT/BIOS setup (which uses GPT but
>>> legacy boot) :-(
>>> 
>> 
>> What same problems? I don't think we've touched how gptboot has handed off
>> to /boot/loader in a long, long time. It there's an issue here, it's a
>> different issue.
> Ok, strictly speaking it is different issue with same "high-level"
> description: pmbr/gptboot has less features than simplest oldest boot0.
> 
> pmbr/gptbood doesn't have any way to select partition to boot from, as
> "boot0" has. No, setting "nextboot" from live system is not a solution.
> I speak about NanoBSD situation when there is tow partitions, both
> bootable, one marked as "active" ("bootme" on GPT parlance) but it is
> completely broken and user need to boot from other one form very
> beginning. This task is trivially solved by "boot0" in pure-MBR case.
> What about GPT/Legacy and GPT/UEFI?
> 
> -- 
> // Lev Serebryakov
> 

errm.. you press a key and enter device and or loader path. if it is not working - the code is there to be fixed. GPT does not have the concept of active partition.

My suggestion would be to walk all those boot programs and document them, then see what features are possible to bring to sync.

rgds,
toomas