You should know that there is always a risk of installing un-supportive software.

They gave us free software. It's us, who do not backup our stuff, irresponsible!
You should give them more thanks for their intentions even the software don't work.

Believe me they try their best but sliderotation, for example, is the stuff that modifies the kernel so it's more dangerous than a normal app.

But I also think Nokia irresponsible for not fixing known kernel bugs (confusing of mmc1/mmc2 on the N810 for example) than anybody out there just spend their time to build an app for us to try out.

You should do a backup now; then re-flash the N8x0; then restore; then your N8x0 will behave normal again.