I only need to flash binaries to the Vegaboard, I currently have no need for debug capabilities.
After reading parts of the reference manual, I found that the Kinetis Bootloader is available in ROM. Unfortunately, I cannot see an USB connection of the bootloader over the native USB port of the Vegaboard with holding the NMI button while plugging in.
Additionally, the flash drive emulation on the OpenSDA USB connector does accept memory images for ARM in the pop-up drive, but reports a fail afterwards. I tried with raw binary, intel hex and motorola srec format, but with no luck. The board continues to run the accelerometer demo; at least, it should have crashed after writing a different binary.
I am using Debian stable OS, may I have to update the OpenSDA firmware for the drag-and-drop flashing to work ?
Regarding RISC-V, it seems as if the ARM bootloader could fill the flash memory after a full erase, and a snipplet of ARM code could change the FOPT contents afterwards. Another idea would be to use the M4/Zero-Riscy combination.