I don't know what rock you live under, but the substrate contractor that made multiple revisions was less than intelligent, however management kept using him instead of replacing him until last revision(which didn't even happen if memory serves)
All the problems they had were due to crappy work and the shituation we are in is due to them trying to remake new/better revisions and just creating more problems... basically throwing our money away.
Of all the boards shipped and sierras shipped, i would assume around 90% failed due to power supply/damage from it going, the rest due to faulty board design, i can't image many boards are functional at this point.
The chips are just fine, they been proven to work on actual boards that were designed by someone with actual intelligence.
Well I see this as a design failure from the start. HF complicated itself by designing such a power hungry chip. If they kept the power consumption lower (aka less speed) they wouldn't have so many headaches with the board/substrate design. Of course retard troll icebeaker will say that it was just a failed venture and it is true. Because the path they started was the wrong path. Instead of being engineers that weight every pro and con they went the marketing way aka BIGGEST/FASTEST ASIC CHIP EVER which caused them a lot of problem that could be avoided with a slower chip.