I have been using QGIS and Grass for ages and while I've noticed this issue before, I've not been bothered by it until now. It is (hopefully) a bit of a noob question but when I open GRASS in the QGIS Processing toolbox, I notice that a lot of standard utilities appear to be missing (e.g. r.in.bin and others - There are only 161 commands listed for Grass 6.4.3 and this figure should be much higher).
I am not talking about add-on plugins but standard parts of the GRASS toolset (according to the Grass documentation). Looking in the Grass bin folder, however, I can see the are there. It is not that the bin folder is not recognized as I can see many of the other utilities there in Processing. I have tried updating to the latest version of QGIS (2.18) with OsGeo4W and re-installing both Grass 6.4.3 and 7.2. I have checked the paths in Processing-options and all looks fine (in as much as the paths point to the top-level directory in each case as they always have).
How can I make the missing ones appear in the Processing toolbox?