{0,ATT_PERMISSIONS_RDWR,16,sizeof(my_OtaData),(u8*)(&my_OtaUUID), (&my_OtaData), &otaWrite, NULL},
https://github.com/slacky1965/electricity_meter_ble/blob/main/src/app_att.c#L300
Меняем на {0,ATT_PERMISSIONS_RDWR,16,sizeof(my_OtaData),(u8*)(&my_OtaUUID), (&my_OtaData), &otaWritePre, NULL}...