The betterblock printed fine without any shuddering in S3D... Really no complaints there. I then sliced a high polygon model with many small features and the printer shuddered like crazy while printing the small details, ultimately completely ruining the print... Its strange, because the raft printed perfectly, but the moment it started printing the models first layer, the printer completely freaked out.

In regards to bricking the qidi controller: did the people that bricked their controllers set the fuse bits properly? Did they use the atmega2560 bootloader that dan newman has on github. I dont see how you can brick a board if you simply use the right settings. An atmega2560 and atmega8u2 are what they are... As long as you use the right settings it should work.

My worry is that qidi used a very old version of sailfish that did not properly navigate small features and small loops (especially on high polygon models)... It could also be that sailfish firmware itself has issues with applying acceleration to *some* small features... And we only rarely hit the limitations of the firmware.

All my firmware settings are good, and acceleration is turned on. My jerk setting is at 7. I could reduce it further, but i doubt that will fix it.