My organization has been using an ancient version of IAR for RL78 - V1.40.3. I decided to try and move us to the current century, so I downloaded and installed V4.10.1. I wrote a simple hello world LED blinky program for our target microcontroller (RL78/G13). It compiles and links just fine, but 999 times out of 1000, it freezes when attempting to flash and debug:

Staring debugger session: Loading debug file

E1: Erasing flash...

It freezes in exactly the same manner, regardless of whether the E1 pins are connected to my microcontroller. It remains frozen until I physically disconnect the E1 debugger's USB connection to my computer.

I have successfully flashed and debugged a grand total of about 5 times. There is no rhyme or reason to when it will work, or won't work. But it only works about 1 time in 1000. I have no idea why.

Here is how I configured the hardware setup for the E1:

Please note, the old version of IAR still works without a problem.

Troubleshooting steps and summary of what I have tried and experienced: