If you are following my guide you need to use their reformat tool, my files only support reformat not autoinstall.
Only 2 people seem to have GPS issue's out of 100s, me being one of them but I've flashed many times with no issues for testing purposes so not quite sure what happened
Downgrade to 19200 or 19101 using my optional extras section
Master reset or use forscan to re enable. Sirius is not a thing in the UK so can't help further unfortunately.
follow the guide
Look through the comments and do research most issues are usually solved by a master reset or forscan configuration
Yes you can upgrade any sync 3 and no you can't go back below 3.2 after using this reformat method.
It's technically not needed but my files are designed for reformat not autoinstall so it's needed for my files