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

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