Appreciate any thoughts on this conundrum!
To give some extra background - I've got the Pi configured to automatically overwrite the mass storage device filestore upon boot, so it is always presenting a fresh filesystem. Each system below (that I'm connecting it to) is made by a different manufacturer and is a closed system, so I have no ability to perform any diagnostics at that end.
System 1 - Always works System 2 - Shows no USB stick connected System 3 - Gives error when trying to save (memory error) System 4 - Says unidentified USB (Windows PC - Always works) (Linux PC - Always works)
At first I thought this was due to minor subtleties of how the g_mass_storage device was being presented as a standard Sandisk USB memory stick works fine in all systems.
However I then started to notice some unusual behaviour, if rather than doing a reboot (and wiping it fresh), I kept the power running and moved it between machines.
If I started with System 1 first, then systems 2, 3, 4 would all recognise/write to it OK.
I then copied a backup of the filesystem after it had been in System 1 - however that still didn't seem to solve the problem after a reboot. What I did then notice though was that if I powered the Pi up and then first connected it to a Windows system it then worked fine when plugged in to the others. To be clear I didn't read/write any files to the device, just started it up, then plugged it into Windows, saw the home directory on the USB open, then unplugged it and plugged it into one of the other systems - they all now recognised it.
I tried starting/stopping g_mass_storage but that in itself didn't seem to do it.
To be honest I'm now a bit flummoxed! It is clearly able to work with all 4 systems (I've been able to save files from them), but it seems to want to be plugged into either a PC or System 1 first before then working with the others. Can anyone think of anything that is happening when I do this? Unfortunately the idea of doing it this way is just not workable for what I'm wanting to do. Ideally I would have 1 Pi for each system, plugged into it just by the one USB data/power cable such that when the system powered on the Pi booted and then the USB was available to it to read/write.
Thanks in advance for any thoughts/suggestions!