NV+ not booting after firmware update #25355252

I believe I have the same problem.

Tried to update the firmware to 4.1.14.

1. First from web UI from remote.

After some time it gave the message "ERROR writing” or something like that.

I rebooted. It seems to be fine.

1. Downloaded the 4.1.14 image to my PC and tried to upload it to ReadyNas NV+. After some time it asked me to reboot in order to upgrade. Went to reboot options in Web UI, selected power down and reboot and clicked apply.

Nothing happened.

Try to reboot manually with power button. It did shut down, which took very long time comparing to the normal and never booted up again.

The symptoms are:

If I try to boot normally it displays checking quotes from 1% to 100% and while doing this it's visible in Raidar with status System starting. Then it goes to displaying only "BOOTING” on LCD with all 4 disk lights are on, activity light is off and power light slowly blinking.

If I try to boor with option "skip volume check" it shows Disk 4 sync for about an hour during which I can see it with the same status in RAIDar, with all 4 disk lights on, activity light blinking and power light slowly blinking and then ends up in the same state as with normal boot above.
And I can boot it in Tech support Mode. It will display a number I am not supposed to post here, but it is working.

I think firmware either on the disks or in the FLASH is corrupted.

So what are my options now?
I think I need to do System reinstall or USB recovery.

Which one I supposed to try first?

If it's OS reinstall what else except user/password to default and network setting will be lost from my current configuration?

The same question applies to USB recovery. What would be lost in this case?

From what I understand both methods will keep my volume, shares and data, which is my ultimate goal is.

Thanks