Hi:

Please understand that Firefox is NOT available for iOS (iPhone, iPad, iPod Touch), Windows Phone, Windows RT, Bada, Symbian, Blackberry OS, webOS, Android-x86 or other operating systems for mobile:

Please see Will Firefox Work on My Mobile Device for more details.

Thank you.

^ You need to update that comment in a ways as they are working on Android-x86 version.

Anyways the Nokia E90 I found is a old device from 2007 and uses the Symbian OS 9.2 and has a too slow ARMv6 cpu at 332 MHz.