Burning Bootloader to custom arduino due

I ordered a custom pcb of the arduino due. Essentially the exact same thing with some minor changes.

I was wondering if anyone could assist me in trying to burn the Arduino bootloader to it?

I tried using an arduino Uni and connecting it to the MOSI, MISO and SCK pins (along with reset 3.3V and GND) however i either didnt do it correctly or it doesnt work.

Its essetially the exact same as an Arduino Due.

Regards,

Isaac.

You don't actually need to load a boodloader onto the microcontroller- it it stored in ROM.