Firmware

Flashing controller

For this operation you need J-Link clone programmer, like this:

Aliexpress 5.49$

All these steps need to be done with both controllers!

Unlocking controller

First of all download and install SEGGER J-Link 6.70b

And download J-Flash project

• Connect programmer's pins (VCC, GND, SWC, SWD) to PCB's pins (same pins, marked by silkscreen).
  • You can connect only SWC and SWD pins, in this case, power PCB via USB-C (please, make sure that battery not installed and power switch in OFF positon).
• Connect programmer to PC via USB cable.
• Open JFlash.
• Choose Open recent project and choose project file, that you download earlier.
• Click Start J-Flash

After that:

• Connect to controller: Target --> Connect (make sure that connect between programmer and PCB is stable, hold wires tight in PCB!)
• After succesfull connect: Target --> Disconnect

Bootloader

Download Adafruit nRF52 bootlader

Move bootlader hex file into root directory (as example: C: disk for windows)

• Open JFlashLite, select NRF52840_XXAA if it doesn't at program start.
• Select bootloader and press Program Device, wait for flashing.

Flashing Firmware

• After flashing controller you need to download ZMK firmware files:
  • ZMK firmware
• Extract archive, move files from groupbuy-release to a directory of your choice
• Connect only left half PCB through USB Type-C, push reset button twice
• Move jiran_ble_lite_left.uf2 file into opened explorer window (just like moving files to a USB flash drive)
• Do same step with right halve (make sure, that you moving jiran_ble_right_left.uf2 file)

After this you can freely connect your Jiran keyboard to PC!

References

Joric's flashing instuction (a lot of variants)

luantty2 flashing instruction