In case you have this problem with the FRDM boards: You are using the FRDM bootloader mode (it shows up as BOOTLOADER) or the MSD mode (e.g. it shows up as FRDM-KL25Z) (see OpenSDA on the Freedom KL25Z Board) and it does not respond any more, or does not work as expected, then read on…

It could be that the virus scanner is the problem: Try to disable it (completely) and check if this helps. If yes, I suggest that you keep it disabled during OpenSDA MSD operations (loading new SDA files or using the bootloader). You might consider to boot Windows in ‘safe mode’ to check if this helps.

Why? Some virus scanners try to scan every new device attached to a system, which includes MSD (Mass Storage Devices). This makes sense e.g. for USB memory sticks or USB disk drivers which could have a virus on it. The thing is: the OpenSDA firmware/bootloader emulates such a MSD, but is not a full MSD device (there is no full file system behind). The K20 processor of the OpenSDA acts just like a file system, but might get easily confused if ‘weird’ accesses happen, or if the host tries to write other files to it than the S19 or SDA file. This e.g. could happen for Mac computers or if your host has some ‘acceleration’ software which tries to index a driver/device.

So if you have issues with OpenSDA Bootloader and MSD mode:

1. Disable virus scanner as it could check the drive and confuse it.
2. Disable any ‘real time protection’ of any special software/firewalls which could read/write to the device.
3. Do not use any special ‘file commander’ or ‘shell extensions’ which try to do extra stuff with the device.
4. Copy the SDA or S19 files with the DOS shell copy command.
5. Do not copy/drag&drop S19 or SDA files from archives to the drive: unpack them first, and then copy them.
6. Do not use Windows 8.1 preview (see this post about it).

Using a file system (MSD) for a bootloader is a very handy thing. It is usually easy and it works. But as with anything: there is no perfect solution. But knowing what is behind it and what could cause issues usually helps ;-).

Hope this helps 🙂