I've had to deal first hand with the fallout of encouraging users to run rpi-update, particularly because it, and anyone advocating it, makes no effort to explain that you're installing untested, unreleased, bleeding-edge firmware which could have any number of breaking changes or incompatibilities.
Yes you can undo it, but that doesn't mean anyone should do it in the first place. And it definitely doesn't mean it should be recommended willy-nilly without at least some effort to explain to present and future users why it's a terrible, awful idea and they should not under any circumstances get into a habit of doing it.
What happens is roughly this:
- User updates
- User is happy and forgets that they ever updated
- Problem occurs with something else
- Maximum Frustration for user and anyone trying to support them
- ... wait a minute, did you run rpi-update?
- Facepalm, facepalm for everyone!
Most of the earlier problems with rpi-update were caused by old Pi Camera tutorials recommending its use, despite the fact the firmware had long since been released and available via apt-get. When device-tree was emerging, a lot of users would still blindly run "rpi-update" as a debugging or magical fix step despite it being unnecessary. The next time they tried XYZ product they'd find it wouldn't work and they'd have no idea why.
Now I feel I need to jump in and make sure we don't set that same precedent again with the LCD. Because 6 months from now everyone will have forgotten about all of this, and any flakiness with the touchscreen will lead people right to forum threads and tutorials that say "Just run rpi-update and everything will be fine."
I hate to hijack a thread to make this point. But things like this end up wasting an awful lot of my time and no-doubt the time of others. I can't stop you recommending it- but please, please have some consideration for the repercussions.