I have a North American model.
And I know there are various "country" versions of firmware.
(Mine will not print CD's)
But with no hacks, my 850 shows ink levels, as well as the low ink warning,
but at that point I just refill, and snap it back in and continue printing,
with FULL ink showing. and no need to reset any chips.
Perhaps that I never let any cartridge get completely empty, the chips never
need to be reset ?
And I do know a person who saw mine, and then bought an 860, (the newer
version of the 850) and they have all kinds of problems with chips and
refills, but the 860 uses different cartridges.
A side note though.
There is a definite ink life improvement between my refills, and brand new
canon replacement cartridges.
Which seem to only be about half full when you buy them.