Did you sign an agreement when you purchased the hardware stating such? If it's the EULA, can you just not read/agree to it before you modify the phone? Also, EULA may be a contract but it's not law.
Contracts can require you to agree to things that are otherwise illegal for them to do. IANAL, but to give an extreme example, Motorola can't ask you to rob a bank in exchange for the ability to purchase a device. There are things such as the First Sale Doctrine (not necessarily applicable here, but still) that dictate limitations that a seller of a copy written entity (copyrights on a physical object, sigh). Such things could maybe render parts of a EULA moot depending on local laws. Again, IANAL.
