Beginning with troubleI recently bought a KL25Z board out of curiosity, they have Arduino form factor, are super-cheap and boasts an ARM Cortex-M0+ MCU!
I got the board home today so naturally I wanted to test it right away.
I plugged it in and the board lighted up with a bright RGB-LED shifting colors, nice! A helpful usb-drive was connected for me to inspect...
Unfortunately I followed the quick start guide from here! Which told me to update the MSD (mass storage device), it said "It is likely that the version provided in this package is newer than what was preprogrammed on your FRDM-KL25Z."... I fell for that easy trap... upgrade something that works... well I followed the instructions and upgraded the MSD by dragging and dropping it onto the BOOTLOADER OpenSDA. Restarted the board happily and BAM! no more drive.
No freaking drive!
I could still access the Bootloader drive and after a while I found the link to http://www.pemicro.com/opensda/index.cfm where you can read under http://www.pemicro.com/opensda/faqs/faqs.cfm that the old bootloader version does not handle Linux and has to be upgraded on an old Windows 7 PC... Well I registered on pemicro to be able to download the drivers http://www.pemicro.com/downloads/download_file.cfm?download_id=378, loaded the board in bootloader mode and dragged the new bootloader software to the board. restarted and also updated the MSD driver. Reconnected the board on linux and now it works... time to test another program...