Still Issues with ext. SSD and iMac 2020 (T2)

I tried the latest release from Tim with the bugfix but still get the INACCESIBLE BOOT DEVICE Message.

Has anyone a better experience?

I did the following:

  1. Made a Image (filebased) from my working bootcamp partition on the internal Apple SSD

2.Restored that Image to my external thunderbolt SSD (Transcend StoreJet 500 Thunderbolt SSD) which I used also with my former iMac 2017 as described in this video

  1. I injected the drivers from the Apple WindowsSupport pack with Winclone (successfull)

  2. I made the SSD EFI bootable with Wi nclone Tools

  3. I tried to boot from the SSD (EFI)

It failed again with the INACCESSIBLE BOOT DEVICE Error Message :frowning:

Injecting drivers will only inject the Apple drives and I doubt it would be helpful for booting to an external SSD. The issue is that after the preboot process finishes, Windows loads the mass storage device drivers for recognizing the startup disk. There is likely no driver for seeing your external drive from the Windows side. It may be possible to create a external bootable installation drive and then see if Windows can see the SSD when booting into the bootable installer with the cmd prompt open. If it doesn’t show up, you can then use drvload to try loading the driver. There does seem to be a driver available:

Here is the article on creating a bootable drive and injecting drivers:

I know this is a pretty indepth process and totally understandable if you want a refund instead. I just didn’t want to give you a “sorry, give up” message :slight_smile: