As you know Prusa Mini finally got Input shaping (ALPHA). It works fine on some of the printers but others get an X Homing error. I Tried couple of things but adding C Clip to the x axis worked. 

Tightening the X axis belt also worked, but it had to be really really tight so i was worried it shortens the belt life drastically. Using the C-Clip, the homing worked with previous belt tention.

I printed 2 clips from PLA, but also works with 1.