The following message is shown every time that I launch the Browser application, and am given the choice between Browser or Firefox: This device does not meet the minimum system requirements for Firefox. The phone that I currently have, and have installed Firefox 4 Beta 2 for Android and Maemo is a T-Mobile® Comet™. I've also included two links (one where I downloaded Firefox 4 Beta 2 for Android and Maemo,) and the other link is to provide detailed information about this mobile phone. I can install Firefox 4 Beta 2 for Android and Maemo perfectly fine without any problems, although I must first select "Unknown Sources" to install Firefox 4 Beta 2, and de-select "Unknown Sources", which is the default values. Firefox 4 Beta 2 for Android and Maemo is downloaded directly from: http://www.mozilla.com/en-US/mobile/download/ For details and information about my phone, below is a link: http://www.t-mobile.com/shop/Phones/cell-phone-detail.aspx?cell-phone=T-Mobile-Comet