Apple has deliberately nobbled the firmware built into its latest generation of Power Macs to prevent them being upgraded to Motorola's upcoming PowerPC 7400 (aka G4) processor. That's the shocking claim being made by Mac-oriented Web site AppleInsider, citing unnamed sources. According to the source, "Apple has intentionally disable the ability to use a G4 processor card in the current Blue and White G3s via its new firmware update. We know this was done intentionally because the previous version of firmware does not have a problem with the presence of a G4 processor." The firmware now checks the host computer's processor, and if it finds a PowerPC 7400, it allegedly halts the start-up process. In short, if you add a G4 upgrade card to your blue'n'white Power Mac, it will always fail to boot. The change was made possible because the new G3s, like the iMac, store the firmware in a Flash chip. Older machines, like the original beige Power Mac G3, will be unaffected -- their firmware is stored on ROM. So how likely are the rumours to be true? Circumstantial evidence suggests they might well be. With a die size many times larger than the current PowerPC 750 chips (see Naked PowerPC G4 seen on Web) yields on the new chip are likely to be low, pushing up prices and, more importantly, limiting supply. Preventing existing G3s from working with the G4 would severely limit the demand for upgrades, in turn cutting down the number of chips upgrade manufacturers require, and thus increasing the number of chips Apple can buy. And once Motorola is punching out 7400s at a more reasonable rate, Apple can issue a new firmware update, removing the G4 block from the code. It all sounds very feasible. The only snag is that there are still a great many non-blue'n'white Power Macs out there whose owners would like to upgrade to the 7400, and who will be willingly supplied by the upgrade vendors. So how many extra 7400 chips Apple really would gain by limiting upgrades this way is open to question. It will be interesting to see what comment Apple makes, if any, on the rumour, and whether the AppleInsider sources' claims are verified by others. ®