System update Ventura iMac with external SSD fails for second time

[Mac Hammer Fan]

A friend of mine has an iMac 21.5-inch 2019 3 GHz 6cores with fusion drive.
Last year, he bought an external Samsung SSD T7 to boot from there.
As with the update from Ventura to 13.3, things went wrong again with 13.4.
After updating to 13.3, he got a bootloop after which the computer kept rebooting. We then wiped the SSD and reinstalled everything via a Time machine backup.
Now it is the same again. The bootloop now also gets a message "Your computer restarted because of a problem." A prohibition sign then appears. How can we avoid this in future?
TIA
🧐

 

[Mac Hammer Fan]

We erased the external SSD and reinstalled Ventura 13.4. Importing from Time Machine went not without problems. We had to choose an earlier backup than the one from yesterday.
We can't boot in the recovery mode. It seems the recovery partition is missing. Can this be a problem for future updates?

 

[Fishrrman]

"It seems the recovery partition is missing. Can this be a problem for future updates?"

My guess is that you skipped something when erasing the external drive.
(read on)

The proper way to erase an external drive is to:
- open disk utility
- now, a VERY IMPORTANT step:
- go to the "view" menu and choose "show all devices"
- finally, in "the list on the left", select the line that represents THE PHYSICAL DRIVE (external) and then click "erase".

The point is to wipe clean the entire drive.
This should result in a new recovery partition being installed with the rest of the OS.

Again, just a guess.

 

[Mac Hammer Fan]

Thanks Fishrman. When I visit my friend again, I'll check it.

 

[Riad]

I am having the same problem. I have invested many hours trying to update my OS to Ventura 13.4. I have Ventura 13.2.1. I never had these issues with OS X. I don't know what to do. Today again, I spent two hours with a kind support person from Apple, and the problem persists.

 

[Mac Hammer Fan]

I think you need to use an usba cable instead of usb c