This will sit like this (it continues to log output into the output file) until the phone reboots. At that point, the adb logcat job will terminate, and the name of the zip file will be indicated in the logfile in a message similar to:
W/SystemUpdateHelper( 64): !!! REBOOTING TO INSTALL /cache/desirec-ota-104882.7b1e5cca.zip !!!
Then, take the name of the file and paste it on the end of android.clients.google.com/updates/partner, for instance, for the Eris 1.17.605.1 OTA, the complete url is:
https://android.clients.google.com/updates/partner/desirec-ota-104882.7b1e5cca.zip