Another lengthy post just disappeared. Damn.
Yes, Charles. Your thinking parallels mine, except that you seem to know what you are talking about.;-)
The STB seems to record on anything. It works with a SD card in a card reader, and all three of my flashdrives. The 8Gb one takes 2hrs of video, but I've never tried longer files. Just the big one that I bought specifically for the STB that gives problems, and then only on files approaching 2 hours.
I've also thought of leaving the current shortened programme on it, and seeing if it will fill the rest of the drive up, in 3.8Gb chunks.

I used to have a Seagate program that would examine HDDrives in minute detail and allow partitioning and other mods. It would be nice to get a similar program that worked on flashdrives.
That 16Gb drive is a Toshiba, which I thought was a pretty good make.

I said the cheap STBs have traps. This one can be programmed to switch on and off at selected times, but NOT to switch on and record! You can also only record the TV channel that you're watching.
What bloody use is that? Only to record a whole evening when you're out of the house.
Don't buy cheap STBs. Chris.