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]

I've tried this on two laptops with two (sort of three) different operating systems.

Dragging and dropping the J-Link binary onto the nRF51-DK doesn't work for me in any of the following situation:

• OS X 10.10
• Windows 7 x64 running in Parallels on OS X 10.10
• Native windows 7 x64

In every case, it shows up as "Bootloader", I drag and drop the latest J-Link firmware downloaded from the My Pages account (as of 20 Nov 2014),and when the file transfer is through the device seems to reset on it's own followed by a fast blinky. When I do another power cycle, it goes back to the CMSIS-DAP firmware and the bootloader shows up again.

I've run through this a dozen times with and without the IF-BOOTLOADER button being pressed, and I'm unable for the life of me to apply the J-Link firmware.

Has anyone been able to switch from CMSIS-DAP back to J-Link? We need a J-Link interface for development here since all of our makefiles and test scripts use the J-Link as the flash interface. I'm currently using an external J-Link, but this is far from an ideal solution any time we need to be mobile with the kit.

The new boards look great ... I just wish I could debug them with the same tools we use on the PCA10001.

Any concrete suggestions, or can anyone confirm they were able to switch?

I have PCA100028 V1.0.0 with the timecode 2014.39.

[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.