I do also have the problem with the IDE Upload. Even with the old IDE. It has something todo with the Chrom/Serial/USB connection. My workaround is the connect and reconnect until i see the ESPRUINO Version information:
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I do also have the problem with the IDE Upload. Even with the old IDE. It has something todo with the Chrom/Serial/USB connection. My workaround is the connect and reconnect until i see the ESPRUINO Version information:
Connected
=undefined
After that procedure uploading works as expected but much slower.
Sacha