I managed to get pen input packets on my tablet:
0a 00 02 21 97 43 2f 32 d1 04
0a 00 02 21 45 41 df 30 18 06
0a 00 02 21 0a 43 3f 2d d7 06
0a 00 02 21 56 47 16 2b 80 07
0a 00 02 21 4f 49 68 2d 91 07
0a 00 02 21 80 47 49 30 c5 04
0a 00 02 20 d5 44 23 30 00 00
0a 00 02 20 a4 43 87 2f 00 00
0a 00 02 20 97 43 84 2f 00 00
0a 00 02 20 8c 43 82 2f 00 00
0a 00 02 20 82 43 80 2f 00 00
0a 00 02 00 82 43 80 2f 00 00
0a 00 02 00 82 43 80 2f 00 00
0a 00 02 00 82 43 80 2f 00 00
last 3 int16 values are x, y and pressure.