Re-partitioning; Adding swap partition; Using GPT partitions

[Arwen]

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also. if you are dd-ing beginning of one GPT partitioned disk onto another one, you get bogus drive. the must be unique GUIDs (for the disk and every partition) are not unique and also the Back up GPT header and partition array are absent. these two are severe violations, that make such setups just a broken thing, working by accident. and, of course, sooner or later, it may "pay off" in a very unpleasant way. GPT partitioning CANNOT be made by dd-ing!

In my example, "dd" was only used to copy the boot loader and other information that @danielt clarified with his partition enhancement. Litterally the next section of my instructions say to use the partitioning tool, ("fdisk" in this case), to create a new GPT label and empty partition table. I can probably make those instructions clearer.

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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.

Exactly.

Yes, this is all clumsy

Ideally we would have been given a proper OS installer which has either auto-layout, or manual layout for partitioning. But, ARM is different in needing specific things for booting. And each SoC needs it's own disk configuration. Perhaps a few years from now, we will have a template for booting, that has each SoC's support details. In our case, 3 separate blocks of code, at specific offsets. Plus, something for "/boot". And last, what devices are supported, in which order, (SPI, eMMC, SD card).

That comment about a proper OS installer is not meant as a criticism of my Pinebook Pro. This is somewhat where Linux was originally for x86. What we end up with, is easy installations. Not yet with alternate architectures, like ARM & ARM64.

Last, it has been a recomendation for a few years on AMD64 / x764 to have something like this, in case the boot loader needs more space.

Code:

/dev/sda1       2048     10239      8192     4M BIOS boot

There is a reserved GPT label just for that purpose.