Hi!
I have 951G-2HnD device. I could upgrade it to 6.42.1 with no problems. After that - no more. There is no difference between “check for updates” → “download&install” or downloading routeros file and manually uploading to Files (and then reboot). RB can download newest update, bet cannot install in any ways. After reboot it has the same software version installed. Is there any way I can see why? Log file doesn’t say anything related.
Is Netinstall the only way to upgrade further?
Yes, that is issue in your installed version, AFAIK it was solved, just netinstall with “keep configuration” and all should be fine.