To the iRiver support site:
In the top page right corner enter "E100" and all support for the E100 player shows up.
Click on the required New Firmware e.g. latest version 1.22 to get more information ( sep 25, 2009 ).
"-. Customers who purchase E100 can upgrade their players either
by Firmware updater or Iriver plus3".
A page shows up for how to download and install the firmware.
Right click the firmware updater
and select "save target as...", for a place to save the installer.
Getting Iriver plus 3:
In the left column of the support page select Plus 3. Next left click Download iriver PLUS3 and save the execute file iplus3.exe .