I have J-link EDU it worked with 6.12 and 6.16 firmware.
After update to 6.20c I got message: "The connected J-Link is defective" with jlink.exe standalone and with IAR debug. Debug breaks.
Two others my commercial J-Links BASE and PLUS works correctly with 6.20c
I have tested EDU with different SW and FW wersions, 6.12 SW works with correctly with 6.12 and 6.20FW, but 6.20SW display error with all FW versions.
How to fix it ?