https://devzone.nordicsemi.com/f/nordic-q-a/112956/unable-to-connect-dfu1. Hi currently i am using nrf52840 sdk ver 17.1.0 s140 sd we have added UART in the secure bootloader/ Bootloader_ble_debug 2. we can able to send multiple bytes once ie 53 46 30 04 02 01 00 FF 00 00 45 46 on reset of device 3. we have sending throughen-USTelligent Community 13Thu, 08 Aug 2024 05:59:58 GMThttps://devzone.nordicsemi.com/thread/497411?ContentTypeID=1Thu, 08 Aug 2024 05:59:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c1d4ae1c-3aea-4ac3-ba7e-5ae3c32dda7aHieu<p>That&#39;s good to know. I will close this case then.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/497404?ContentTypeID=1Thu, 08 Aug 2024 05:28:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:85242041-4de5-498e-bb6a-93cb91236e6eAP1<p>we can able connect now it is working fine</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/493714?ContentTypeID=1Fri, 12 Jul 2024 19:18:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b2e2a2bb-2dc7-4783-92bc-45a6f8d4a0d2Hieu<p>Hi AP1,</p> <p>The log you provided show no errors at all.</p> <p>Can you enable more log on the bootloader and see if there are any BLE issues logged?</p> <p>Can you also get the log from the mobile app?</p> <p>Hieu</p><div style="clear:both;"></div>