@syzygy
No, it's me missing something [between the ears!], and i'm blind coz you're right i've got the wrong file shown. Actually, my eyesight is really cr*p so i'll use that excuse rather than the lack of brains one. Thanks for picking that up [the file error, i mean .... oh, and the brains thing too then....]

The whole point of my ramblings is because of my unsuccessful attempts to find the PCB PN's in the fw's of 310 [hwid 0566] and 610 [hwid 0569]. The string 58 42 4C 4B 53 [XBLKS] appears twice in 310 and once in 610, but unlike with another related fw [300 hwid 0476], a XBLKS entry isn't followed closely by the PCB PN/s, and searching for 31 30 35 2D [105-] of course yields nothing either. In another, 310MLC [HWID 0856] i can't find XBLKS or 105-. However, a search of 105- in 300MLC [hwid 0855] finds the PCB PN 105-00968-M0.

So is it that these 310 & 610 fw's don't have the PCB PN's written into them or is it just not possible to find them by search?