the Nokia N8 uses Symbian OS and also has a ARMv6 type of cpu (not ARMv7) which also makes it not compatible even if it had Android 2.2+ anyways.

https://wiki.mozilla.org/Mobile/Platforms Symbian

  We currently have no plans to develop a full Firefox browser for the Symbian platform. See Mobile/Symbian for notes from an inactive project to port Firefox to Symbian. However, a future version of Firefox Home may be available for Symbian.

Oh sure copy+paste one of my posts without credit.