I was fearless and tried what happend if i call the "EraseLogSector" function on my G11.
Result: (As hopped/expected) The romlog was cleared. So if you or canon ready out the romlog,
only a file with the content: "No romlog saved" or so is written to SD-Card. But calling EraseLogSector
does not get rid of the E31/SubCpu error message, it will still be there on the ver.req screen. It looks like this information is stored somewhere else in the camera flash.