Hi all - pls excuse the novel, but would appreciate any help/ guidance.

I received the Huawei HG659b modem when I upgraded to fibre, and thought I would connect a USB hard drive to an unused USB port for media sharing etc.  I had an old 500Gb hard drive around (Western Digital) and when connected, and the appropriate Samba & media sharing buttons were clicked, it worked ok.  I could access it from laptops and from my smart TV.

But the end-game was to connect a new 4TB hard-drive, from Seagate.  But while the modem "recognises" the hard-drive is connected, I can't connect to it from my wireless devices.

I've formatted the hard-drive, contacted Seagate (quite unhelpful), I've re-booted and factory-reset the modem, I've contacted Spark (really no help) and I've called Huawei (who incidentally do not support this model any more...) but I still can't work out what I'm doing wrong.  The 500Gb drive works fine; the 4000Gb drive doesn't.

I suspect there might be a limit to the size of hard-drive that is supported by the modem, but there's nothing in the user guides that states that, and Spark says "I'm sure you can connect USB device".

So I'm at a loss as to what is the problem - would appreciate any thoughts/ advice.

Thanks!!