I haven't heard much about this, but am curious. The AT&T and unlocked iphone models (A1428) support LTE on band 4 (LTE). Since LTE is backwards compatible with GSM and HSPA, it seems like Apple disabled this feature as the iPhone only gets EDGE on 1900 on T-Mobile. Would it be possible to enable AWS HSPA+ through a jailbreak tweak or a custom ipsw or something?