AT&T is the only carrier currently offering the Moto X in the U.S. and it also has the exclusive on the neat Moto Maker customizing tool.

The other U.S. carriers that will offer the Moto X are expected to gain access to Moto Maker from November onwards, but for now interested smartphone shoppers can customize their Moto X only if they get it from AT&T.

In Canada, meanwhile, the new Motorola flagship handset is exclusively available through Rogers for now, but the carrier does not offer the much-touted customization features.

It's worth highlighting, however, that AT&T will allow its subscribers to customize their new Moto X only if they are eligible for an upgrade. This means that those who want to purchase the handset contract-free, without committing to a lengthy agreement with the carrier, will not have access to the customization features. The contract-free Moto X costs $579.99 and comes in the standard black or white color options.

The news comes from DroidLife, which reports attempting to purchase two 16GB Moto X units for a giveaway only to be denied.

"I just stopped off at two AT&T stores to try and pick up a 16GB Moto X 'Design It' card to giveaway on the site, so that one of you lucky DL readers could customize your own phone, and was denied. I worked with a rep for a solid 30 or so minutes at one store to try and figure out how I could purchase a card for the full retail amount of a Moto X, but his system was locked into forcing the cards to be attached to an account and to only be used with upgrades," explains the publication.

"In other words, you can't buy a Moto X 'Design It' card in store at full retail at this time and then head to MotoMaker.com to customize your own phone. You can only purchase a card if you have an upgrade available. Since MotoMaker is only half working at this time, that certainly limits some of its potential customer base at the moment."

This strategy may seem a bit odd or unfair to some, but it actually makes sense for the carrier. Making the Moto Maker customization tool available only to those who are willing to upgrade allows AT&T to attract more subscribers who yearn to customize their own smartphone and keep them hooked for longer.

Motorola did not confirm whether the other U.S. carriers will indeed get access to Moto Maker from November onwards, so AT&T is the only option for now. Sprint, Verizon Wireless and T-Mobile are all expected to add the Moto X to their respective lineups, but none of them has made an official announcement so far.

Previous rumors suggested that the Moto X would launch on all four major carriers on Aug. 23, but it seems that AT&T was the only one to get it. There are also a few whispers that Verizon may start offering the handset on Aug. 29, but it remains unclear whether it will come with Moto Maker as well or whether AT&T actually has the exclusive on the customization tool for the next few months.