Hello All,
First, thanks for this post: https://devzone.nordicsemi.com/f/nordic-q-a/40924/how-can-i-restore-the-original-bootloader-of-a-pca10059 ; I'm attaching the file here again JIC.
7242.pca10059_bootloader_mbr_v1.0.1.hex
And, in case anyone else thinks they've bricked their nRF52840 dongle when all looks well trying to load the Bluetooth Low Energy scanner and getting the 'can't open serial port error':
Apparently, if the virtual com port opened is greater than 15??? (Not verified - but == 20 -> fails) - you'll need to remap it under device manager to be ideally less than 10.
After reading a lot of posts; including one that said the dongle was 'bricked' (and after putting the programming header on it) - I tried reducing the com port from 20 to 6 and it worked.
So, apparently, nRF Connect for Desktop (currently circa v3.10.0 at the time of this writing) can't handle a com port setting of 20 or greater when programming the nRF52840 dongle - just like when this bug was originally seen on PC's +20 years ago when com ports > 9 were first possible under the host operating system.
Regards,
johnwest
