User can't download my app after Google Market Update
Make sure that your application manifest isn't making any requirements for hardware capabilities that the device doesn't actually have. It's possible that some capability that you were requesting was taken away in the device's firmware update; if you are requesting any capabilities in AndroidManifest.xml via uses-feature, make sure that you set required="false" for anything that you can use but don't actually require for operation. Common culprits are trackball and certain classes of multitouch support.