The recently released ROM Update for the beige G3 range of machines contains an element that renders them unable to use G4 upgrades, said Newer Technology.

A report on the issue on the MacWeek site states that an Apple employee wrote on the Tech bulletin board system: "Notes to consider after reading this [thread] include the fact that there is no shipping or announced PowerPC G4 processor upgrade from Apple or, as far as we know, any other company and we're not aware of any documentation that indicates any Power Macintosh G3 computer was marketed as being upgradeable to a PowerPC G4 processor." No record of this contentious statement now appears online.

The existence of the anti-G4 fix, which prevents a G3 from starting up if the owner has installed a PPC7400 upgrade processor daughtercard, was confirmed by upgrade specialist XLR8: "A special fix will be needed to run G4 with the 1.1 firmware in a blue-&-white G3. Users get five [warning] tones...We have a fix in hand."They went on to explain: "Additional AltiVec performance software with blue-&-white compatibility is being readied in our labs now."

Upgrade manufacturers have also said that G3s, with the 1.0 firmware, are not limited to which CPU they use.

Meanwhile Robin Sharp, director of marketing for PowerLogix, said she isn't prepared to wait. "We are confident we will have a workaround" by the time PowerLogix' G4 upgrade cards are scheduled to ship in late fall. "We will advertise blue-&-white upgrades as long as they are compatible."

Finally, a note from Apple employee Todd Hart (tech support): "Was this done intentionally? From our perspective at the user level support, we don't know. We do have a request in to find out yes or no. Will there be a software update from Apple? We have a similar request in on this." To close, he said there was not much else he could say.

In the future, the response from accelerator manufacturers seems to imply that an upgrade path for G3 machines will be independently manufactured.