Apple has issued an internal memo to Apple Stores and Apple Authorized Service Providers providing technicians with guidance on how to diagnose and address the iPhone Duo's inner display cracking issue, MacRumors reports.

If a customer reports the problem, Apple advised technicians to inspect the device and repair or replace it under standard procedures. While the instructions are straightforward, the fact that Apple circulated an official memo suggests the issue is widespread enough to warrant formal guidance.

The memo states the issue affects a small number of units, consistent with Apple's public statement to CBS News: "We are aware of an issue impacting the inner display on a small number of iPhone Duo units."

Reports of cracked displays began surfacing almost immediately after the iPhone Duo launched on October 23. CBS News spoke with Jesse Dalton of Frisco, Texas, who said the phone "just got super tight about halfway up the hinge" and then "snapped" with a "loud pop" before he even finished setup.

Roneshia Smith told CBS News her device cracked less than 24 hours after purchase, describing "an egg cracking" sound, and said staff could only offer a replacement that was backordered.

MacRumors notes that most reported faults run along the hinge, producing a line of bright pixels, and that Apple says impacted units exhibit the defects rather quickly after usage.

The response is notable for how quickly Apple acknowledged the problem. TechRadar's Lance Ulanoff told CBS News he was "shocked" Apple responded at all, calling it untypical of the company, while suggesting the ultra-thin glass in the multi-layer folding screen could be the most fragile part.

MacRumors reports that iFixit, after completing a teardown of the device, believes the issue is likely related to a defective hinge on affected units — though Apple has not commented on the underlying cause.

The stakes are high: the Duo starts at nearly $2,000 and tops $3,000 for higher-end models, and it is the first major product rollout under new CEO John Ternus.

There is no iPhone Duo recall, and Apple has yet to launch a public-facing repair program on its website for this issue, MacRumors reports.

For now, the company's advice is to contact AppleCare for a replacement, with support available on Apple's website or by calling 1-800-APL-CARE in the U.S. and Canada.

Ulanoff recommends making an appointment at an Apple Store rather than walking in, and while backordered replacements have left some owners in limbo, CBS News noted at least one customer got a same-day swap.

MacRumors adds that Samsung has already mocked the display cracks in a new ad campaign, so pressure is mounting on Apple to contain the problem.