I tested the write instinct and the nybble scotch and calibrated all the servo's. this was all successful.
But when using the communication protocol I can only sent one command e.g. sit and nybble will sit. after this commands no new commands are accepted. Tis behaviour is the same with the IR unit. Sometimes the servos rotate to unexpected positions and block the joints.
However the "m" command does fuction as it should for all servo's. The command "h" and "j: also do not work.
I reloaded the software and recalibrated the servos and mpu both the fault stayed the same.
Please HELP.

Does your Nybble behaves like in this video?
If so, try to connect the jumper switch SW3 between BATT and V_S.
What's your batteries' parameters?
Yes Nybble showed the same behaviour as in the video. The battery is use is unprotected.
Thanks again.
I changes the jumper switch to batt and now nibble works fine. Thank You for this lovely project.
I use a battery from Ultrafire 1200mA 3,7 V.