General Issue:

In file jsinteractive.c, line 176, the if statement will always execute for telnet. This results in de-muxing and re-muxing any UART pins that are otherwise assigned (in my case, to I2C1), due to the jshUSARTSetup() call.

It seems that telnet doesn't have DEVICE_INITALIZED_FLAGS set, or is false. It may also be that the ESP32 code isn't setting it correctly, but I'm not well versed in C.

Either way, I've worked around it by adding another if statement around the test for jshDeviceInitialised(device), with a simple:
if (device != EV_TELNET) { ... }
I expect this is a less than ideal solution, but it works (sort of) for now 😄

Random details

I posted on the forum about this, and kept digging around until I found the work-around.

The work-around is not ideal. After connecting via telnet, you can not go back to USART without a reset() (or power off). In my case, this ok because I'm running the device via a wall-wart and not USB.

Also, this may be exclusive to ESP32, but I don't have anything else to verify the issue.

I also noticed that jshardware_common.c only has InitInfo for USART, SPI & I2C. Perhaps something about telnet should go in there? Perhaps not. I assume that if there was something there, the jshIsDeviceInitialised(device) call would return true. again, I'm probably way off.