I've read dozens/hundreds of posts saying the opposite, that either or both of the firmware updates DID fix the problem.
Perhaps those still complaining have a DIFFERENT problem altogether, one that requires AppleCare just as any other manufacturing problem outside the "firmware-fixable" curve...let's just not continue the ******** of saying that Apple has lower build quality standards simply because a few vocal users (out of millions) are facing issues; Olsen's Theorem is disturbing enough when we discuss economics.
The fact that the problem is, for most people, very intermittent, indicates that applying the fix and then saying you're not getting flickering within a few hours afterward is not likely to be indicative either way of whether there is a fix. Lots of people said the PRAM reset fixed it for them too, followed by lots of people saying the first firmware update fixed it for them, and I'm sure each time you said, see, no problem, Apple fixed it, or see, maybe anyone who still has issues has a different problem, just like you are now.
I don't know who's complaining about Apple build quality other than to say they do not deserve to be known as any better than other PC manufacturers, which certainly seems justified here, but in any event, your bias in that regard is readily apparent when you describe the problem as "a few vocal users (out of millions)" - unless you work in Apple support,
you have no idea how many users have the problem except that out of the tiny fraction of people who participate in online Mac user forums who would see where to take a survey and then bother to go do so,
hundreds have logged these problems. Come on man - don't try to assert what you for some reason
wish were the case to be fact. Since the problem is intermittent, and we know that it has recurred since installing the update for some people, based on evidence to date, it does not appear that Apple has fixed the problem. If you want to argue that they may have fixed one version of the problem for some undefined number of people, while others in fact have a different issue, knock yourself out - perhaps they did, and perhaps they didn't, but I haven't seen any credible evidence of that so far.