(First post, so also hi to everyone)
I bought one of this type via OnBuy and I've had a similar issue, although I am able to inject Hekate 6.0.0, and only 6.0.1 won't work. I've followed the instructions to update its firmware, so maybe that's why it managed to work with 6.0.0 (although I'm not sure, as that firmware update might not be as recent as that [EDIT: That firmware update was at least a year ago, I see now]). I've found the best way to use it is to trash the payload.bin in the ATMOSPHERE_HEKATE folder and then copy a replacement that's already been renamed to payload.bin, as when I tried to rename a file that I had copied over, the RCMLoader seemed to crash, with a bluish light remaining on even after I unplugged it from the computer. In this state the computer could no longer see it (thought I had bricked it). I fixed it by locating the reset button, which, once pressed, turned the light off and it was back to normal.
I'd also previously bought another RCMLoader from AliExpress, which can't be accessed via a PC, but appears to be loaded (like another one mentioned upthread) with an unknown version of Hekate that works anyway (which is all I really need, but I bought the other one, in the hope it would be a fully functioning one). This one only ever flashes blue, apart from when you charge/connect it, then the light shows solid red.
Anyway, they both work, for now, as also mentioned upthread, booting up into Hekate 6.0.1 (by presumably looking for the Hekate 6.0.1 bin file on the root directory of the SD card.)