Hello,
We have a nRF52840 on our board, whose fw we would like to be able to update through both BLE and UART (the MCU is connected to a ST32 MCU via UART) using a bootloader, possibly with minimal changes wrt the examples included in the SDK 
Up to now only the BLE secure bootloader version has been used and it works well. I took a look at the UART secure version, which doesn't seem to require the softdevice (while the BLE bootloader requires the s140 SD), and the two projects seem to differ only by the sdk_config.h file, the main being the same.
I have a few, probably naive questions (I have only a few days' experience on the Nordic ecosystem):
1) In order to have a BLE+UART bootloader, would it be enough to merge the sdk_config.h content of the two projects?
2) Since the BLE bootloader uses SD s140 and the UART one does not, would the BLE+UART bootloader be ok with just the s140, or does the s140 need (somehow) additional modifications as well?
3) As far as I understand from the Nordic documentation (please correct me if I am wrong) the serial DFU is performed using the SLIP protocol. IS it already implemented somewhere inside the bl firmware, so that one just has to send data from the host MCU according to the SLIP protocol, or should the user implement the protocol also on the Nordic side?
Thanks!
Regards,
Stefano
