The Nokia E5 (also known as the Nokia E5-00) uses Symbian^3 (S60 3rd Edition, Feature Pack 2) as its base OS, but Nokia’s internal ROM building & packaging system for this device is what you’re asking about with “Rpkg” — which refers to ROM package format and deep-level firmware structure.
Flashing the RPKG File
Downloaded firmware files must be placed in a specific directory for Phoenix to recognize them: C:\Program Files\Nokia\Phoenix\Products\RM-632 : On 64-bit systems, the path is Nokia E5 Rom Rpkg
Completion: Once installed, the Nokia E5 will appear in your device list. Selecting it will allow you to run classic Symbian apps and N-Gage 2.0 games at native or upscaled resolutions. Flashing Original Hardware (Stock Firmware) The Nokia E5 (also known as the Nokia