How to revert nRF51-DK interface MCU firmware back to the J-Link image?

[aaronxu]

As nRF51-DK User Guide said: "If you have swapped to the mbed image and want to revert back to the J-Link image, download the latest SEGGER J-Link software from www.segger.com and open a debug session to update to the latest J-Link OB firmware version."

I press Reset button and plug in the USB cable, then the LED5 is blinking. After that, the USB identification changed from MBED to JLINK. But it still can not be recognize by nRFgo or Keil. that means I can not use nRFgo studio to flash or erase nRF51822, or even use Keil to debug it. It's still looks like mbed interface.

PS: nRFgo studio Version 1.17.1 Keil Version 5.12 Segger J-link ARM V4.74b

Thanks.

[K. Townsend]

Just as a FYI for anyone else stumbling across this, the issue seems to be anytime I insert the board into my macbook (my main development machine), even with Parallels installed and redirecting to Windows, OS X corrupts the contents of the bootloader and the J-Link firmware is lost. It seems I just need to restrict any development with the new 32KB parts to a Windows only machine until this issue can be addressed, though it's kind of a shame to have to keep two development environment open. Thanks for the heads up on the 10.10 issue, though!

[Tüze]

Hi Kevin, Glad it worked! Yes it's not nice being restricted from an environment, but the good news is that the fix for both jlink and mbed/cmsis are on the way to address this issue and will be released soon.

[RK]

That board works fine for me as a JLink device on OSX 10.10. Yes OSX fails to mount it as a mobile disk device and you get an error that it can't be mounted, however it still works perfectly well as a JLink under OSX (with V4.94c). OSX isn't corrupting the image on it, it's the MBED firmware which is reporting a filesystem OSX can't read (and so assumes to be corrupt). MBED is working on that and the same driver is ALSO embedded in the Segger software so that you can switch between them.

So switching between MBED and JLink may be a problem on OSX, but using the board with the JLink software on it as a JLink device works perfectly for me, it's just like the old dev boards in that respect.

[K. Townsend]

You're right. Updating the OSX J-Link drivers to 4.94f (latest as of today) finally makes it appear as a J-Link on OS X 10.10 as well (ignoring the mass storage drive issues). Thanks for the tip.

Appreciate the rknrfgo J-Link wrapper as well ... I've been using it for ages as a replacement for nrfjprog, as well as the sniffer utility (although we have enumeration problems with it using these boards since it doesn't recognise FTDI based devices, perhaps because it's looking for a specific VID/PID combo: www.adafruit.com/.../2269 ... I'll have to dig into the Python API myself). Completely off topic, though ... just wanted to say thanks for the tools to make OS X easier.

In summary: update the board on a Windows PC, update the OSX drivers to 4.94+, and the J-Link should be fine on OS X 10.10, other than the annoying dialogue box due to the mass storage drive.

[minted]

I wish I had found this comment earlier ;-) Just finishing my first successful flash on OSX 10.10 for my nRF51 dongle, also using rknrfgo and mbed IDE (compilie .hex) and s110 softdevice flashing.

1. First I flashed the blinky sample to verify that a .hex is starting
2. Flashing the S110 softdevice
3. Using a sample to verify the correct softstack "BLE iBeacon"
4. Verified working iBeacon with nRF Master Control Panel Android