Thanks @Tell, I'll give it a go. I've phoned a local reputable car audio firm and they've confirmed that, if it goes wrong, the unit is simply removed from the car and thrown away because there is no longer any hardware or software available. At least I know what I'm up against.

It will go fine. There is a validation check made on the sla1 signed files which stops rubbish being loaded into the unit. Then the normal process has a roll back if interrupted so restarts from a restore point. You normally drive about and after 30 - 40 mins you get the update. The other way is to start it off and open and close the door every 15 minutes. That allows the process to run through without interruption. The infotainment unit keeps live by opening the door. Power goes on for 20 minutes. 15 minute period gives you a grace 5 minutes. I do mine on the backend menu but that isn't for beginner. Just shows you what is happening.

 

The units have a built in SSD so like modern PCs, laptops etc designed to be updated. I wouldn't worry.

 

As posted I got the latest installed without issue (350):

 

 

From Vag PDF Same for all VAG cars.

 

Installing the map material
• Insert the SD card into one of the SD card slots on your vehicle until it audibly clicks into place.
• Now select the “MENU” button on the Discover Pro. Click on “Update software” in the “Setup”  
menu under “Version information”. Now follow the instructions on the display of the Discover Pro.

 

Unzip, copy across then above.

 

 

Edited 27 October, 20231 yr by Tell