Hello,
thank you for the great tips on how to restore a bricked XPenology. I got inspiration from the tip to use an older USB stick and took it from there without removing the drives. I have a second Synology that has all folders replicated, so I was not afraid of losing data if this would not work.
The situation was as follows:
I was running 5.2 with Nanoboot for a couple of years and decided now to go to 6.x
I created Juns 1.02 Stick and migrated without problem to 6.1.7. All went well.
Then I updated via the GUI to 6.1.7. Update 3 (the feedback on the forum was that it is no problem, just a restart is needed) and from that on the system was working but no GUI and not found in the finder (neither via browser nor Synology app). I restarted several times, the box sent me emails that there was an improper shutdown, the files were accessible via network, the webstation websites were OK, I just could not get into the frontend and find the machine.
The solution was:
1. Reboot with Nanoboot USB stick, option install / upgrade
2. Find the machine in the Synology finder (there it had a DHCP address and state was 6.1.7 15284 migratable - this was the first success...
3. changed the USB stick to the Jun 1.02 loader and
4. installed a fresh version of 6.1.7-15284.
All went well but after the 10 minutes waiting period it said that it cannot connect to the Synology. It was still in the Synology finder, so
5. I rebooted with Juns USB stick and did another install (again those 100% and 10 minutes waiting and hoping) and then I got to the Synology setup window / name, user etc.
The data is there, but I need to set up all apps and users. Maybe I could have tried the migration instead of new install in steps 4 and 5, but I wanted to clean it up anyway from users, privileges, firewall settings and old apps I did not use.