I’m not very familiar with bash script yet, maybe in the future i can help in this regard.

First, get the linux portable source code in http://fms.komkon.org/ColEm/

The current package is ColEm29-Source.zip

Unpack the zip file (type unzip ColEm29-Source.zip)

Now, go to the ColEm/Unix and type make.

After compile and before to run colem, is necessary put the bios COLECO.ROM in then same folder. I found the “ColecoVision BIOS (1982).rom” on web and rename to COLECO.ROM.

Create the folder “/opt/retropie/emulators/colem” and put the colem binary and COLECO.ROM there

Now, create “/RetroPie/roms/colecovision” and edit es_systems.conf:
<system>
<fullname>ColecoVision</fullname>
<name>colecovision</name>
<path>~/RetroPie/roms/colecovision</path>
<extension>.rom .ROM .col .COL</extension>
<command>xinit /opt/retropie/emulators/colem/colem -sync 130 -skip 0 %ROM% </command>
<platform>colecovision</platform>
<theme>colecovision</theme>
</system>

If emulation get too fast or slow, set the sync option.

—–

Note: On my config.txt, framebuffer_width is setting to 320 and framebuffer_height to 240. To adjust screen to get better on my TV, i edited ColEm/Unix/Unix.c:

#define WIDTH 410 //272 /* Buffer width */
#define HEIGHT 300 //200 /* Buffer height */
…
int UseZoom = 1; /* Zoom factor (1=no zoom) */
…
SetVideo(&ScrBuf,80,50,WIDTH,HEIGHT);