The update process is tedious and unreliable, and you can't work around or 'restart' .
I have a Discover Pro, and the SD card is 16GB with total space used 6.3GB. Everything is file structured under 'maps' directory. I updated this once back in 2019, but this was after a few tries.
The file download is done in chunks, then stitched together into one big .7z file, this is unzipped and copied to the card.
For this year's June update, DiscoverCare Win allows you to use a new device.
I downloaded the whole 26GB, then got a micro SD card with adapter, and extracted the zip file to it.
File structure was Mib1 and Mib2 as top level directories.
Putting that in the car, it didn't want to use it, but if I put it in the car and had the old SD card, it said 'software update is available' but did nothing.
So I thought maybe I'd done something wrong by unzipping myself, and went through the whole download and copy once more to a clean SD card.
That didn't work.
I went through the whole process once more using the original SD card and it updated and worked, though this, according to DiscoverCare Win is 'Discover Media Gen 2' , despite the fact I have a Discover Pro !
I did a block by block (Unix clone) copy of my updated 16GB card to my 32GB card. This didn't work in the car, despite the fact that this is how you can clone ANY disk to another using a Unix system.
So I have a Discover Pro unit, it's using Discover media , go figure ...