Did you find a solution for this?

For custom Service: 00003970-817c-48df-8db2-476a8134ede0.

#00: Custom Characteristic: (00003971-817c-48df-8db2-476a8134ede0) (Write only)

#01: Response (00003972-817c-48df-8db2-476a8134ede0) (Notify Only)

#02: PICC NOTIFY (00003973-817c-48df-8db2-476a8134ede0) (Notify Only)

If I get a card close to reader I do successfully get a notification

00003973-817c-48df-8db2-476a8134ede0 (2 bytes): hex: 50 02
So subscription seems to be correct

The prob is that no matter what I write over #00 , response back is always the same..

E.g:

BLE: write #00 62 00 00 00 00 00 00 00 00 00
Value changed for 00003972-817c-48df-8db2-476a8134ede0 (19 bytes):
utf8:   U
  ♣S       ♣ Y?
hex:    55 00 00 0A 00 00 05 53 00 00 00 00 00 00 00 05 00 59 AA

BLE: write #00 FF CA 00 00 00
Value changed for 00003972-817c-48df-8db2-476a8134ede0 (19 bytes):
utf8:   U
   S       ♣ \?
hex:    55 00 00 0A 00 00 00 53 00 00 00 00 00 00 00 05 00 5C AA