procount wrote: ↑
Tue Jan 14, 2020 7:30 am
There are a few OSes that already use U-boot on the pi. Whenever I come across it in an OS I am converting to NOOBS or PINN, I have to strip it out and revert to the standard bootloader because it prevents multi-boot.
It seems U-boot needs to exist on the first partition and all partition references seem to exist buried in compressed script files. So to my mind it offers no advantage whatsoever in the Pi environment.
Interesting decision. I'm unsure of exactly how far U-Boot's scripting capabilities go, but it almost
seems to have enough to provide a menu of choices of what to boot. Meanwhile my goal certainly can provide a menu of choices.
My target is to get a working GRUB setup. GRUB is well known and all of the configuration I need for it is readily available. Thing is (to my knowledge) there is no way to directly boot GRUB on a Raspberry PI. Worse, if GRUB was being directly booted I would be concerned about how readily the setup could be maintained. GRUB doesn't receive that many updates, but it does get some. Worse right now I need a crucial feature which is "bleeding edge" for GRUB.
As such the Tianocore/EDK2 UEFI bootloader and U-Boot are two options for loading GRUB. I'm concerned with the status of the EDK2 project. There are sort of working versions for the RP4, but those are far
behind the state of U-Boot. Worse the direction being taken seems likely to make things worse for a time before they get better.
As such I'm back to taking a look at U-Boot.
ehem wrote: ↑
Tue Jan 14, 2020 2:42 am
's notes look fairly usable.
Problem with this is those directions appear to assume booting an armhf kernel and simple adaptations haven't gotten them to work with an arm64 kernel. This is to say nothing of trying to load GRUB.
Apparently the standard for loading aarch64/arm64/armv8 images is to use the UEFI protocol. U-Boot has a "bootefi" command. Figuring out how to make everything work has so far been troublesome.
Andrei Gherzan's directions have gotten me to something which appears
to load a aarch64 Linux kernel, but once the "bootm" command is executed the RP4 stops responding.
I'm no where near out of ideas, but I'm certainly shy of my goal right now.