Hi, I have a MKIV DVD nav unit for an E39 M5. I attempted to upgrade it to v32 software. Here is what I did:

1. Burned a v32 on lowest speed onto CD-R media

2. Installed the software - it went in fine, but I realized that I forgot my custom splash screen

3. Burned a v32 on lowest speed with custom splash

4. Tried to to downgrade the DVD with a v22.1 disk. This installed until near the end when it had an error on the media.

5. Then tried to re-upgrade to v32 with the custom splash. This reloaded things, but instead of rebooting at the end it just went to a blank screen. I waited a few minutes and figured I will need to try again.

6. I shut off the car and restarted. The nav screen was blank (black), but functions such as radio continue to work ok.

7. I tried to see if the OS would reload, but it would not.

8. I burned both a DVD and CD version of v32 to try both. Neither worked.

9. I unplugged the cables from the unit for an hour. I plugged them back in and tried a disk again (it will eject disks if I press on the button a couple of times).

10. I tried unplugging the battery on the car for 20 min. I then tried with the v32 again, but same problem.

11. I hooked up the I-Bus serial and I cannot get the NAV unit to respond on the bus.

12. I swapped a MKIII into the system and the MKIII worked.

So now, the unit has the red power light flash and I can hear the disk spin, but it does not seem to get anywhere. I would hope there is a way to reset the unit so that it is ready to reload the software. Any help would be appreciated- I hope I did not brick the MKIV.