Unable to upgrade firmware

Certain firmware versions prior to 4.0.4 have problems with firmware file uploads. On EG4xxx (Core/Pro), if firmware upload fails prior to v4.0.4, install v4.0.1 followed by v4.0.4:

  1.  Install v4.0.1: Download
  2.  If successful, install v4.0.4: Download

Newer firmware versions can be installed normally via online-connected download or manual file upload (latest versions available via eGuard).