That's the same YouTube video that prompted me to try the audio extractor from Amazon.
The one you got from Amazon does appear to be the same unit as mine but I suppose there could be a slight spec difference or maybe even a fault with yours.
I suspect that the internals of these things can vary quite significantly over time e.g. as the original silicon is replaced with newer/cheaper stuff that on the face of it does the same job but at the detailed level maybe doesn't - especially if it's not the primary function of the thing, which in this case is sold
as an audio extractor rather than an HDCP bypass device. As well as that, eBay and Amazon (and no doubt Aliexpress and the like) are full of all sorts of devices that look pretty much identical, and claim to do the same things, sold under lots of different brand names - and sometimes no brand name at all. It's very difficult to know exactly what's inside any one of them (without opening the case) which does, unfortunately, mean that one all too often ends up in this tedious buy-try-return cycle. Even one which carries a brand name of some kind and comes recommended can easily have updated/cheaper/somehow different hardware inside (as was even the case with the HDR FOX-T2, in fact).
Thanks for the bootloader info. When mine turns up from eBay (currently forecasting 28th December
) I'll make sure to give it a go with that version. (BTW, is your Humax' software version the same as mine?)