https://devzone.nordicsemi.com/f/nordic-q-a/28503/nrf52840-sdk14-x-nrf-usb-driver-problemHi Engineers! We used SDK13 for our Project (multilink BLE with 1xServer &amp; 4x PeerS) and now move to SDK14.2, almost done except only USBD. if we use SDK13 driver , our PC aplication (HID EP1) works very stable (we use USB for BOOTLOADER en-USTelligent Community 13Mon, 27 Nov 2017 11:57:36 GMThttps://devzone.nordicsemi.com/thread/112794?ContentTypeID=1Mon, 27 Nov 2017 11:57:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b4c42b16-5ff9-4fd3-b271-e523c890fd15Sigurd<p>Hi,</p> <ul> <li> <p>Are you using custom boards, or nRF52840-PDKs? If you are using nRF52840-PDKs, what version of the board are you using ? (<em>It should be printed below PCA10056 on the sticker on the kit.</em>)</p> </li> <li> <p>Are you seeing this issue on all boards ? or just some boards?</p> </li> <li> <p>What do you mean USB transaction fail ? Are you running into the error-handler ? have you checked the return codes while running in debug mode?</p> </li> </ul> <p>Also please take a look at the SDK 14 Migration guide <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v14.0.0/migration.html?cp=4_0_2_1_7_7#migration_usb">here</a>.</p><div style="clear:both;"></div>