Add docs for upgrade from legacy table to gpt about disko HOT 4 OPEN

* Does `flags = ["bios_grub"];` directly map to `type = "EF02";`?

yes

* For blueberry host (first link), I have ESP partition starting at 1MiB and ending at 512MiB. Examples seems to specify `size` instead, which, if I understand it correctly, would brick my boot. Are `start` and `end` options still supported?

you can also specify start and end instead, but even changing your disk layout won't run disko again and your disks will remain the way they are now. What is important though, is to create a partlabels disko would have created if you would run it with the gpt type.

* Is `bootable = true;` flag still necessary for ESP partition?

no, it never had any effect on gpt partitions.

* Do I need to specify `priority = 1;` for ESP partition?

some people say it's necessary, but I never had a device where this was an issue. it shouldn't matter for the ESP partition but the EF02 partition could be important.

* For cloudberry host (second link), do I need to specify `fs-type = "fat32";` for my boot partition?

fs-type never had any effect on gpt partitions.

* How did the API change in GPT format compared to legacy table format? What endpoints had breaking changes? What endpoints aren't supported anymore? What are deprecated? What have better implementations ready?

the newer gpt format uses attrsets instead of lists. the legacy table used parted the new gpt uses sgdisk, which has a better interface for scripting.

Perhaps the above questions are trivial to answer, but I haven't found any docs for them. And I would like to err on the side of caution when it comes to changing the filesystem layout.

from disko.

I would also very much appreciate a guide on how to move from table to gpt.

Or a definitive statement that it's not possible and we either have to a) live with the warnings or b) re-install.

Ref: #538 (comment)

from disko.