Is your bootloader damaged? Just use the Cas 3 + to repair it as there are no more updates for this cam anyway.
It will mean taking the cam apart and doing some soldering work.
Alternatively van hoof electronics will repair it for you for a very reasonable price.
Yeah that's the problem Mickha, have tried to repair it with Cas3 and have discovered can't repair v4.6 with v4.1, the process doesn't complete. Cas3 includes flash v2.* to v4.1 for the repair routine but no v4.6 ( E-mailed Duolabs with the issue so far they're "maintaining radio silence") however looking at the Cas3 repair routine it looks to me that with a known good v4.6 cam you can lift and make a copy of the flash but I might be reading it wrong.
Thanks for your response.