Hi,
I have bought a GS290 specifically to install /e/, but using the easy-installer (version 11.2 because v12.0 has some trouble running on linux), I get the message that the GS290 is not supported 
From the terminal:
DEBUG e.e.i.tasks.DeviceDetectionTask - checkAdbDevicesResult(GS290CTM100088 device usb:2-1.2 product:GS290_EEA model:GS290 device:GS290 transport_id:1)
Note that the easy-installer requested to activate MTP, but this option was not available, and the phone was detecter when I activated usb file transfer and usb debugging.
Did anyone flash the GS290 successfully?