' store a config file containing WIFI credentials and DNS info'
Unless 'sneaker net' using the SD card was mandatory between the PC and the Espruino device, has the following been considered at one twentieth the cost?
A half inch by one inch PCB with jumpers along with a socket'd 8 pin DIP can be had for less than $1 USD. The chip itself, 5 for $1 USD, but might need a few supporting discreet components. I have a handful of AT24xx lying around to do the exact credential store task. Mine is used with the MDBT42Q using BLE so easy O.T.A. update/save. Just a thought. . . .
Thank you all. I think this will work. I'll probably need some kind of pcb because I'll need to use the SD to store a config file containing WIFI credentials and DNS info for particular installations. So my plan is to write the creds on a Mac or whatever, insert into the SD board connected to the Espruino. When the Espruino boots it reads creds and connects to wifi and starts a webserver.