1. Empty (erase the contents) of your microSD card from the Windows Mobile file explorer or format it from your computer using a card reader (in some cases format doesn't work).(not necessary, do it only if 1st attemt fails)
2. Extract the .NBH file from your prefered ROM upgrade: In windows use winrar (right click) to extract the contents of the exe file. In Linux / MacOS use cabextract.
3. Rename the .NBH file to ARTEIMG.nbh and copy it to the root folder of your microSD card.
4. With microSD card inserted on the phone, start the bootloader (The bootloader is invoked by pressing down the Power & Record buttons and using the stylus at the same time to press the RESET button at the left side), keep both buttons pressed after releasing the reset button.
5. You should see the screen pictured on the left, confirm flashing on screen by pressing the volume slider down.
6. Flashing might hang after some time but this is normal. Just wait. Complete flash takes about 30 minutes, so check your battery or connect to charger before the flashing process starts.
SuperCID devices are able to flash any NBH image using this method.