Up until now, Qualcomm has been silent about the rumored problems it's having with its new Snapdragon 810 SoC, but that changed during the company's earnings call today. According to Re/code, Qualcomm confirmed that the 810 had been dropped by "a large customer." The company is cutting its outlook for the fiscal year slightly, partly because of the lost business and because of fierce competition in China (not to mention an ongoing antitrust case).
The revenue range has been lowered from between $26.8 and $28.8 billion to between $26 and $28 billion. Qualcomm also attributed the reduction to "a shift in share among OEMs at the premium tier" that has caused it to sell more modem chips than SoCs. That shift can almost certainly be attributed to the astronomically high sales of the iPhone 6 and 6 Plus and Apple's growth in China—the iPhones use Qualcomm's modem chips, but not its SoCs.
Qualcomm didn't specify which customer had dropped the chip, nor did it say why the chip had been dropped. Rumors from last week may fill in those blanks, though— reported that Samsung had elected to drop the chip from the forthcoming Galaxy S6 because of overheating problems. LG then came to the 810's defense, saying that it hadn't encountered heat problems in its G Flex 2, but (admittedly non-final) hardware on the floor at CES did seem to be having problems with heat.
Qualcomm used off-the-shelf ARM Cortex A57 and A53 CPU cores because of pressure to go 64-bit, but one gets the impression that they didn't really want to. The company stressed that it's going back to a custom architecture for a follow-up high-end chip that's scheduled to sample to partners by the end of 2015. Qualcomm employees also confirmed to Ars at CES that a new Krait CPU core was in the works, but that's pretty much the only thing we know at this point.