BY GPSrChive at GPSrChive.com forum:


More update info:

We are all very fortunate that the device does not attempt installation, as the 10.20 firmware file is nearly 150% large than the 10.10 version. Seems quite clear something went very wrong when this update was compiled and Garmin did not catch it before publishing.

We will have to wait and see if they upload a new 10.20 GCD or skip ahead to version 10.30.