https://devzone.nordicsemi.com/f/nordic-q-a/42118/pc-ble-driver-v4-0-0I can communicate with success from the pc to my custom nrf52832 device (SDK 15.2, S132v6.1) using the pc-ble-driver (sd_api_v3) with Tag 4.0.0 from Github. Great work! But I can not request a RTU other than 23 from the PC. Values &gt; 23 return Erroren-USTelligent Community 13Fri, 04 Jan 2019 14:44:58 GMThttps://devzone.nordicsemi.com/thread/163991?ContentTypeID=1Fri, 04 Jan 2019 14:44:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c5aad49d-57a9-4481-a33e-7803241889dfChristian Waldmann<p>Hello Einar</p> <p>I can exchange larger MTU with success with the S132_V3 from the pc-ble-driver V4.0.0, after adding the following line to the init for the call to sd_ble_enable(...):</p> <p>ble_enable_params.gatt_enable_params.att_mtu = 150;</p> <p>Thanks for support</p> <p></p> <p>Happy coding</p> <p>Chris</p> <p><span></span></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/163976?ContentTypeID=1Fri, 04 Jan 2019 13:53:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f0f43657-adde-453d-aec6-35bc2a0a990cEinar Thorsrud<p>Hi&nbsp;Christian,</p> <p>A) All connectivity firmwares for SD versions larger than 3 are patched to support MTU size up to 250 (you can see that by searching for NRF_SDH_BLE_GATT_MAX_MTU_SIZE in the <a href="https://github.com/NordicSemiconductor/pc-ble-driver/blob/master/hex/nRF5_SDK_15.2.0_connectivity.patch">patch file</a>).</p> <p>B) No, the precompiled hex files are patched to use max MTU 250.</p> <p>C) The build script will download and patch the SDK automatically when building the connectionvity firmware. You can see the details <a href="https://github.com/NordicSemiconductor/pc-ble-driver/blob/2ee416ab4acd29a765e0fabf8893b105c6016b54/hex/cmake/util.cmake#L225">here</a>.</p> <p>Einar</p><div style="clear:both;"></div>