I've once advised one guy how to update the EE's firmware through PM. So here's the instruction that I wrote then.
Step I (optional): Do a factory reset by installing Golden Dingo.
This is an optional step recommended in cases when your system is messed up and you would like to perform a clean install. All your apps and settings will be deleted. If your unit is working well as it is and you would prefer to keep your data, then you can skip this step and go at once to step II.
1. Download
e-update.golden.zip, put it in the root directory of a USB stick or SD card and rename it to update.zip
2. Turn off your device and insert your update media.
3. Hold the Rotate and Menu buttons on the LCD side and without releasing them turn on your device with the Power button. Keep holding the Rotate and Menu buttons until you see the 'Updating software' screen.
4. When the update finishes the device will restart.
Step II: Update to Ermine.
1. Download
ee_update.zip.ermine-0.9.zip, put it in the root directory of a USB stick or SD card and rename it to update.zip
2. Turn off your device and insert your update media.
3. Hold the Rotate and Menu buttons on the LCD side and without releasing them turn on your device with the Power button. Keep holding the Rotate and Menu buttons until you see the 'Updating software' screen.
4. When the update finishes the device will restart.
Step III: Install the Allmine tweak package.
1. Download
Allmine-Universal-0.4.zip, put it in the root directory of a USB stick or SD card and rename it to update.zip
2. Download
gapps-hdpi-20101114-signed.zip, put it in the root directory of a USB stick or SD card and rename it to gapps.zip
3. Turn off your device and insert your update media.
4. Hold the Rotate and Menu buttons on the LCD side and without releasing them turn on your device with the Power button. Keep holding the Rotate and Menu buttons until you see the 'Updating software' screen.
5. When the update finishes the device will restart.
6. Sign into your Google account when prompted.
Check twice for accuracy in naming when renaming the zip packages. If your OS is hiding extensions, make sure you don't give the files a double extension (like update.zip.zip).