I can't install Mobile Firefox from the Android Market on AT&T Motorola Flipback with Android 2.1. So, I downloaded apk file: fennec-5.0.en-US.eabi-arm.apk from URL http://ftp.mozilla.org/pub/mozilla.org/mobile/releases/ and tried to install with the following command "adb install /data/local/tmp/fennec-4.0.en-US.eabi-arm.apk"and I get error message: Failure [INSTALL_FAILED_INVALID_APK] Note that I can install other apk files with no problems.