Further to Mick's point number 4:
" If you get a 302 programmer busy error that won't go away (the DCS240 programmer is prone to crashing), just power off the DCS240, wait 15 seconds and power on again to clear it, then repeat the DP operation."
This works, as written, if you are using something OTHER than the DCS240's USB connection (DCS240's internal PR3 functionality). Mick stated that he doesn't use the DCS240 USB connection, so the instruction works correctly for him.
But, if you are using the DCS240-internal PR3, the act of removing the DCS240 power may not necessarily clear the DCS240's USB functionality, which may be what is "locking up" and causing the JMRI "302 programmer busy" error. With this scenario, clearing up a locked-up programming track may require removing DCS240 power AND disconnecting the USB cable from the DCS240. But disconnecting the USB cable likely "confuses" the mechanism JMRI uses to talk to the DCS240. And that likely means that you will need to quit JMRI. Once DCS240 power is restored, you may re-connect the USB cable and re-start JMRI.
Regards,
Billybob
