Id be happy to have a clean 8.4.1 but I can't find a way to update it. Is there nothing I can do? It's unfixable? I haven't been able to find a solution anywhere, true, but I also haven't read about anyone else in a similar situation. Is this an unheard of problem? Surely there something I can do??
You can restore to 8.4.1 super easy.
Start by turning off passcode, then turn off find my iPad.
Backup your iPad in iTunes.
Then put your iPad in DFU mode.
iTunes will detect iPad in recovery mode and will restore and update it to 8.4.1
It is that simple.
You have said that you have DFU restored and then jailbroken again which is the only part that confuses me.
If you truly did restore out of DFU mode then it would not have been jailbroken. Which I am assuming is the final goal. However you said you restored then jailbroke again, which isn't possible with pangu?
If you were in DFU mode, and iTunes recovered your device you would have ended up on ios8. Which pangu would not have jailbroken.
So I'm going to assume that you were not in DFU mode and did not recover your iPad.
With your iPad plugged in to your computer, power it off.
(Hold power button for 3-5 seconds, then slide to power off)
When phone is finally off, do EXACTLY this
Hold power on phone for THREE seconds, (apple logo will appear) CONTINUE TO HOLD POWER BUTTON but also now hold the home button for TEN seconds, (Apple logo will disappear but screen will still be backlit) LET GO OF POWER BUTTON ONLY, CONTINUE TO HOLD HOME BUTTON, until iTunes detects iPad in recovery mode. Only then should you let got of the home button.
There will not be any options in the itunes window.
Just click ok and let iTunes do its thing. Your device will come out on a clean 8.4.1 install.