since you have 6.0.0-12, https://github.com/Plailect/Guide/wiki/9.2.0-Update-(rxTools-2.5.2) would be the best thing to use to update to 9.2.0-20. please don't use game cards to update, it will only make things more complicated.
if that doesn't work, try https://github.com/Plailect/Guide/wiki/9.2.0-Update-(rxTools-3.0)
Thank you ! I'll give it a shot shortly.