Sony suspended the firmware update for the Sony A7RV:

We confirmed that some ILCE-7RM5 cameras may not start up after installing the version 3.00 update.
We have suspended the update while we investigate the cause.
(September 13, 2024)

Some readers (including youtuber Peter Gregg ) told me they experienced issues withe the new FX30 firmware update too (But Sony did not suspend the FX30-FX3 firmware update yet). What’s also true is that most testers did not have any issue at all. Weird…