If one sets a breakpoint in bochs and then tries to step after bochs reaches the breakpoint, then bochs doesn't step. A fix can be found at the bottom of this page: http://pdos.csail.mit.edu/6.828/2006/tools.html
Created attachment 100628 [details, diff] patch for bochs step bug
app-emulation/bochs-2.2.6 doesn't exist anymore in the Portage tree. If someone has still the same problem then an update to its latest version would be necessary.