Pi4 Fat32fs - left click or right click

I have a new USB2.0 Memory stick which I am using on a Pi4 as the USB hardware boot (riscos.img, config.txt, etc)

The Pi boots, so the harware must see the files with the correct filenames.

If I left click on the :0 icon the filer opens with RiscOS filecore names riscos/img, config/txt, etc.

If I right click on the same :0 icon I get a ‘Disc not understood’ message.

Can somebody help me understand what is going on because I am confused.

To save anybody asking Drive 4 is on a RISCOSbits PiSSD ^up msata

If I right click on the same :0 icon I get a ‘Disc not understood’ message.

That’s expected behaviour if there is no filecore partition on the memory stick and you have the fat32fs module loaded.

OK Thanks. I can undertand that.

But I have another memory stick with only hardware boot files on it.

If I boot from that, then a right click gives a filer window

SCSI::Pi4.$

Fat32fs::Pi4-Boot.$

How did I get to that? (because that is how I liked it before I purchased the new memory stick.

How did I get to that? (because that is how I liked it before I purchased the new memory stick.

If the FAT partition is <= 4GB then DOSFS will pick it up so right click works.

I am still confused (not an uncommon situation for my ageing brain).

Both fat32fs and Windows XP show the partiition to be 14 GB.

OK, Yes.

The partition is less than 4GB. (checked on fat32fs and Windows XP. It is a 4GB stick.)

So, if I want to build another one, do I need to buy another 4GB Sandisk memory stick.

And does that explain why 5.28 on a Pi4 reads my old 4GB SDcards but does not read my new 16GB cards?

And does that explain why 5.28 on a Pi4 reads my old 4GB SDcards but does not read my new 16GB cards?

16 > 4

And does that explain why 5.28 on a Pi4 reads my old 4GB SDcards but does not read my new 16GB cards?

When you insert a FAT formatted SD card in the SD card slot it doesn’t automatically get picked up by fat32fs. Something to do with the partition number being different for SDFS compared to SCSI. For SDFS drive :0 the command ‘fat32fs:mount -f 16’ should open a filer window for FAT formatted SD cards. For cards <= 4GB DOSFS is used automatically.

Excellent. Thank you so much for the clear explanation. I can now read my new 16GB SD cards.

Writing a 4GB image to a 16GB card. Also makes the SD cards readable.
(4GB is plenty big enough for my purposes_

And it works with USB memory sticks as well. And solves the right/left click issue as well. Everything is good now.