Finally managed to install LMDE from the usb,
the image was made with LiLi USB Creator, the only program on windows that wrote a bootable working image without permission problems.
Unetbootin is completely unusable on windows.
Now I face another problem - after the first reboot, the system at the login screen freezes, refusing any kind of input, the mouse cursor also won't move.
This is probably related to the: "acer-wmi: No or unsupported WMI interface, unable to load" message.
I'll try updating through the recovery console first as soon as I get the opportunity, right now I can only use wifi connection.