Re-partitioning; Adding swap partition; Using GPT partitions

[danielt]

jeez. @danielt, GPT holds partition information in the Partition Array. that has its minimum limit, to be able to hold at least the minimum number of partitions, I can't check the particular numbers, because typing it from a tablet, but the partition array still will be at least something kilobytes. and it comes BEFORE any partition. and now i see, you managed to have the first partition at LBA 64.

A normal GPT with the recommended partition array (plus the protective MBR) runs from LBA0 through to LBA 33 (and is repeated at the end of the disk). It is not a problem to have the first partition at LBA 64.

well, i don't know what all these sfdisks really have been creating, but it's not GPT! kind of not worth mentioning after this, that GPT recommends to align a partition at 2MB.

I disagree. The GPT created from the above script is an entirely conforming (it even regenerates the UUIDs correctly). As mentioned only the first and last 34 sectors are reserved and the 2MB alignment is a recommendation, not a requirement.

Note also that the 2MB recommendation exists to make filesystems that write heavily to the first few blocks (e.g. FAT) more efficient on some media types. That simply isn't relevant here. IDBLoader is the only partition that is not 2MB aligned and that is OK because it is not a filesystem and is seldom changed. There is no problem here.

IMHO it is far better to have proper protective partitions to ensure an OS installer doesn't nuke the system firmware (RequirePartitions tells installers to leave the firmware alone) than to rely on dumb luck. Proper partition labels are also a useful service to help curious admins understand their system without learning through acidentally breaking it.

Frankly I'm not sure who your comment about dd is aimed at. The only use of dd in the thread so far is to copy the firmware from eMMC to SD and the GPT is created *after* the dd.