[SOLVED] Double sided printing problem

arubin, maybe re-try another way "Driver Install Tool" linux-brprinter-installer-2.2.1-1.gz ? from a fresh install i am afraid at this stage.
it prints default one sided on a recent MFC-L2700DW with slackware current & 14.2 both 64 bits, unfortunately not the same printer as yours HL-2250DN
https://support.brother.com/g/b/down...n_eu_as&os=127

root@darkstar# ./linux-brprinter-installer-2.2.1-1 HL-2250DN
You are going to install following packages.
   hl2250dnlpr-2.1.0-1.i386.rpm
   cupswrapperHL2250DN-2.0.4-2.i386.rpm
OK? [y/N] ->

_peter I tried your solution and it appears to have worked. Thanks very much!

I had been using drivers that I downloaded and repackaged in 2011!