https://devzone.nordicsemi.com/f/nordic-q-a/89125/dfu-softdevice-and-app-updateHi. I am trying to update my Softdevice using DFU. If I update from S112 to S140, do I have to upload the application as an image built with S140 as well? And do I need to update the bootloader as well depending on the Softdevice version?en-USTelligent Community 13Mon, 20 Jun 2022 13:01:56 GMThttps://devzone.nordicsemi.com/thread/373251?ContentTypeID=1Mon, 20 Jun 2022 13:01:56 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b795aa5d-c569-4722-8eea-c58758772b2cEinar Thorsrud<p>Hi,</p> <p>The bootloader prevents updates to a SoftDevice of a different type. Moreover we do not test this. That said, it is possible to do a slight change in the bootloader to allow updates to different SoftDevice versions. For that you need to update the bootloader to allow it first, by modifying&nbsp;softdevice_info_ok() in&nbsp;components\libraries\bootloader\dfu\nrf_dfu_validation.c.</p> <p>You always need to update the BLE bootloader when you&nbsp;update&nbsp;the SoftDevice to a different type or different major version. Note that as the bootloader must be modified first you need to do the update in sequence:</p> <ol> <li>Update to the modified bootloader version that support updating to a new SoftDevice type. This should be built for the old/existing SoftDevice.</li> <li>Update bootloader and SoftDevice (S140)</li> </ol><div style="clear:both;"></div>