Here is the image I put on all of the Raspberry Pi plug n play packages I sell:
Just unzip, and burn to an sd card 2gb or larger using Win32 Disk Imager.
It’s made for Raspberry Pi, and it emulates G27 as G29 by default. It auto-starts GIMX and takes advantage of a status led and shutdown switch if available, like so: http://gimx.fr/forum/viewtopic.php?f=3&t=1617
As far as I can tell, the image works equally well on Raspberry Pi Model B+, as well as Raspberry Pi 3 Model B, and I assume everything in between. It’s pretty easy to switch to emulate something other than G27 – see link. It’s based on DietPi, which means it is command line only, no GUI.
I have an older Raspbian image that has a GUI, but it is larger and less conveniently set up. Find it here: rpi_gimx.zip.