There have been a few posting asking how the OpenSDA bootloader works (including from me) without many useful answers.
After a bit of stuffing around I've done a very basic app that loads successfully into the KL20 chip on the FRDM-KL25Z board.
The only requirements seems to be to re-locate the image at an appropriate address.
The OpenSDA loader accepts SREC files (something I only just discovered) as well as the mysterious .SDA files.
Anyway - Attached is a minimal Codewarrior project that loads on the FRDM-KL25Z board and flashes the LED. This is a ARM compiler version but has the additional post-build step to produce a SREC file.
Original Attachment has been moved to: BlinkyOpenSDA.zip