The last Xperia handset to be released on T-Mobile’s network in the United States was the Xperia Z1 that came with a locked bootloader, which crippled third-party development for it. Many potential customers of the Xperia Z3 on T-Mobile feared that the handset will also come with a locked down bootloader, though they have been hoping against hope that carrier had a change of heart and ships the phone with an unlockable bootloader.

Unfortunately for them, it is now confirmed that the Xperia Z3 for T-Mobile does indeed come with a locked down bootloader as reported by many users who had pre-ordered the handset and received it a few days early before its scheduled release date of 29th October.

A locked down bootloader means that gaining root access and developing ROMs and kernels on the T-Mobile variant of the Z3 is going to be a huge challenge for developers.

The Z3 is the first Xperia phone from Sony to be available inside a month of its global availability in the United States. It is also available under the Z3v moniker on Verizon’s network, though that handset is more of a rebranded Z2.