here are some simple steps to writing a PI Risc OS SD card
go to https://www.riscosopen.org/content/down ... spberry-pi
and download the RC14 SD image the first one in the list you cannot miss it. This is a zip file so will need to be unzipped.
Unzip the file to a place on your hard drive it will unpack to give you three files (Readme.txt, RC12 to 14 changes.txt And the important one riscos-02-17-RC14.img
download and install https://sourceforge.net/projects/piwriter/
to your mac then use this to make a SD card for Risc OS please bar in mind that the SD card needs to be 2GB or bigger this it what you will end up with.
Click link https://www.riscosopen.org/wiki/documen ... SD%20image
do not try to run this in your Pi yet you are not done yet.
to your hard drive
(This will convert a RC14 SD card image to the latest suitable ROM, to include 29-Mar-2016 firmware and ROM, with no overclocking commands required, suitable for all models of Pi but, ideally, you should add a kludged ZeroPain module in place of the unkludged one, instructions provided. (Warning) This update is not yet stable on the Pi model 3 as some of the applications provided with RC14 do not run on ARMv8 and will need recompiling.)
mount the RC14 sc card image on your mac it will only see the fat32 part of the image list the files.
You will see these files keep this open
BOOTCODE/BIN WR/ DOS 17:25:24 02-Feb-2015 17 kbytes
.CONFIG/TXT WR/ Text 00:42:18 23-Feb-2015 96 bytes
.FIXUP/DAT WR/ DOS 17:04:26 18-Feb-2015 6 kbytes
.LICENCE/BROADCOM WR/ DOS 13:47:06 10-May-2012 1447 bytes
.RISCOS/IMG WR/ DOS 00:00:00 01-Jan-1980 5 Mbytes
.START/ELF WR/ DOS 17:04:26 18-Feb-2015 2582 kbytes
unzip update4.zip to your hard drive you will see these files
open the folder !Boot inside you will find choices & loader open loader you will see the same files as above
copy these files to your mounted SD card and overwrite the current files above, this will give you a bootable sdcard to use in your PI
Before you close the mounted.sd image check that the files have been copied from Update4.zip and place a copy of the file update4.zip (yes the whole file) for later use.
you are now ready to place the sdcard into your PI and boot for the first time, you are not done yet.
Connect the cables and boot your Pi it might fail to boot because of zero pain issues so make sure you have read step 4 and follow the instruction to the letter.
Hope this helps and is not too hard to follow. when you get to the desktop post a message and we will move to the next lesson.