Comment # 8 on bug 1164310 from Guillaume GARDET

(In reply to Fabian Vogt from comment #7)
> (In reply to Guillaume GARDET from comment #6)
> > The comment in JeOS is:
> > "Map /boot as ext4 to make dtbs available to U-Boot"
> > 
> > For RPi, we need a FAT partition so that the firmware, dtb and u-boot can be
> > loaded.
> 
> That's the VFAT EFI partition. /boot is on btrfs, at least for the SLE JeOS
> and openSUSE JeOS should do the same.

Yes, it is the EFI partition where required files are copied automatically.

So far, openSUSE JeOS uses ext4, not btrfs. 
If we switch to btrfs, we need to warn people about the additional free space
required to avoid 'zypper dup' failures. But this is another topic.