MD16FAST.exe - firmware with rip lock only
MD16ORIG.exe - i think original 2.16 stock firmware
MD15RPC1.exe - firmware with RPC1, rip lock
WINBTYPE.exe - bitsetting tool for DVD+R or DL+R, and DVD +RW (only need to run it once and set it to compatibility permanent (no need to run it again even if you change firmware unless u want to change it back to original DVD+R as DVD+R).
this is the windows flasher version, extract the one you want, run th e exe. let it flash, when it’s done, reboot. then run the bitsetting tool (WINBTYPE.exe).
i suggest you use either Herries 2.17 firmware or TDB (the dangerous brothers) 2.F8 firmware (both same), both have SL and DL bitsetting, RPC1 region free, rip lock. http://tdb.rpc1.org/#ND3500A , i had get results with these.
not sure link for herries 2.17, gotta do a search for it on forum or ask someone.