It looks like some people have received ELLO systems with blank PIC32 chip. This is something that wasn't supposed to happen since I explicitly ordered pre-programmed chips from Microchip Direct. No idea what is the reason for that and apologise if that has happened to someone.
The good thing is that the system can be programmed easily with Pickit3, ICD3, or some other compatible programmer. I have released the most current HEX file for ELLO 2M (not 2M²!) in the project's page on GitHub: https://github.com/knivd/ELLO-2M/
The file is called "MicromitePlus_ELLO_2M.hex".
On the expansion connector there is access to the PIC32's programming lines. Connect the programmer's data line to the pin marked "PGD", the clock line goes to "PGC", and the reset line to "MCLR" (not "MCLRK"). Connect a wire from the programmer's ground to one of the ground pins on the connector. Do the same with the 3.3V line.
Switch the system on and it should be ready for uploading the hex into the chip. Reset it after programming and everything should be working fine.