Currently trying it as well. I also got error 6 in phase 2/2. I think I'll simply copy over the pristine 5.0.0 root image and do an update from there. Much easier than manually uninstalling all hacks. I'll keep you updated.
Update: It worked. Here are the steps I took:
- Make sure that you are using the diags partition with SSH. To install, enable usbnetwork while normally booted, then: dd if=/mnt/us/mmcblk0p2_ssh.img of=/dev/mmcblk0p2 bs=4K
- Create ENABLE_DIAGS file on the "USB drive", and reboot.
- Once in diags, enable usbnetwork by touching the N - U - Z - X items.
- Wait for 30 seconds, then SSH to 192.168.15.244 (user: root, pw: mario)
- dd if=/mnt/us/mmcblk0p1.img of=/dev/mmcblk0p1 bs=4K
- dd if=/dev/zero of=/dev/mmcblk0p3 bs=4K (this resets a few settings, but actual content is still kept)
- idme -d --bootmode main
- rm /mnt/us/ENABLE_DIAGS; sync; reboot
After that, I could update to 5.1.0 without problems. I'll now check the localization procedure (Since 5.1.0 includes french, german, spanish, brazilian portuguese, I guess that these translations are now obsolete; there are still other languages for which this may be useful).