Created attachment 739399 [details]
y2log.tar.xz

Using the JeOS image 2017.05.23-Build1.1 for the RPi1 (armv6l).
When running yast in ncurses to change the bootloader without any update I get
the error message:
Error
Execution of command "[["/usr/bin/grub2-editenv", "list"]]" failed.
Exit code: 1
Error output: /usr/bin/grub2-editenv: error: cannot find a GRUB drive for
/dev/mmcblk0p2.  Check your device.map.

Comparing the content of device.map with the content on my RPi3 it looks OK.

I am able to continue and I get the default "GRUB for EFI", (this is odd, the
RPi1 is not an EFI device) which I change for GRUB2
After that I get the message:
Error
Internal error. Please report a bug report with logs.
Run save_y2logs to get complete logs.
Details: unsuported architecture arm
Caller:  /usr/share/YaST2/lib/bootloader/stage1_proposal.rb:266:in `block in
<class:Stage1Proposal>'

Obviously the architecture is armv6l.