@Simon: I just had the “Toolhead not detected” issue during a print. I reattached the cables, restarted the print and a few seconds later, again “Toolhead not detected”. Turned the cable 180 degrees at both ends, a few seconds later again “Toolhead not detected”. Then I noticed that the data cable was really close to the filament feeding tube, so I turned one of the ends 180 degrees again, and made sure the data cable was on the opposite side of the filament feeding tube. Restarted the print, and … it printed till the end without any further errors. You can see some minor defects where the printing was halted - http://www.thingiverse.com/make:209382 - but I’m still happy with the result.
Could it be that the data cable touching the feeding tube while printing is one of the possible causes for the “Toolhead not detected” issue? I’ll try another print tomorrow to see if I really got rid of the error (if not, I’ll print & use the stabilizer). I’ll keep you posted.