lcd resolution problem

i have a Chinese tablet called I-BOO with board id : k0712b-v3.5
after searching and trying many firmware i finally find a firmware not the original one.
after flashing it the tab turned on with huge fonts on the lcd
every thing was big and go like 10" tablet
someone told me that i can change the resolution of the screen and he did this before with PC without any boxes and of course not APK file because you can not recognize any thing on this tablet
any body heard someting like that
and how to do ????