Recently I had reason to reset the toner count on a Brother MFC device – here are the steps:
Open Cover to drum/toner assembly (And leave it open)
To reset DRUM Counter press CLEAR/RESET then press 1
OR
To reset TONER Counter press CLEAR/RESET then *00 (STAR – ZERO – ZERO)
Close the cover and continue – machine will restart, whirr a bit then should be ready to use in a few seconds