Support for linux as bootloader multiboot based on kexec

[dpeddi]

Since the kernel for each slot is stored into the slot itself, is required to invert rootfs and kernel flashing.

We developed this multiboot solution for vuplus boxes but can work on other boxes with few changes.

[betacentauri]

Hi,

maybe I do not understand how your multiboot mechanism works, but is this change really necessary? Can't you just add the kernel file into the rootfs tar file? Then it will be "installed" without any changes.

[dpeddi]

Images already distributed doesn't consider this multiboot, so I think ofgwrite should take care of this.

Then ofgwrite don't recognize the multiboot system. Fdisk -l give no output

[betacentauri]

Ok. You have added 2 additional changes. Have you finished? Or it is still work in progress? Have you tested the changes on other boxes and without multiboot on VU boxes?

[Ev0-BH]

I have tested the patched ofgwrite with Abcom Pulse4K, it works as it should when flashing the current slot or flashing another slot.

No change in the way it performs.

[Ev0-BH]

Also tested Octagon SF8008, again no issues flashing the current slot, or another slot using the patched ofgwrite

[Huevos]

These commits appear to have no negative impact on other boxes.

[betacentauri]

Thanks for looking into it! Due to my limited free time, I wasn't able to look at it.