RISC OS Software RISC OS
http://www.svrsig.org/ software/Update.htm

Updating Raspberry Pi RISC OS firmware

There are five options:

Update 3: December 2015 firmware, high vector aimed at the Pi Zero, see here.

Update 4: April 2016 firmware, low vector aimed at the Pi Zero and model 3 see here.

Update 5L: October 2016 firmware, low vector aimed at all models of Pi, see here.

Update 5H: October 2016 firmware, high vector aimed at all models of Pi, see here.

Update 6L: October 2016 firmware plus 13-Feb-2017 ROM, low vector aimed at all models of Pi, see here. Includes Serial and GPIO module in ROM. Has some issues with screen mode changes.

Update 8H: February 2017 firmware plus 6-Mar-2017 ROM, high vector including Serial and GPIO modules, aimed at all models of Pi, see below for contents of zip file. This is the EDID beta ROM and contains an updated screen configure plug-in.