First of all: does the fan work properly when it freezes (do you feel airflow out of the left vents), is the unit hot to the touch or not?
Perhaps you can try to do the offline update, instructions are available at INFO: How to do offline software update?
If I’m not mistaken the offline update procedure will tell you it found an update file and maybe warn you it’s the same you already have, but still allow you to apply the update. If the first OTA update somehow was botched it might go better if done offline.
But please reply about the fan status first.