Flashing your ROM means overwriting the software on the phone with custom software. Doing this will usually erase all of your personal data and applications.
I think there's a lot of confusion floating around because there's really two flashing steps involved - flashing the 'recovery' software, and flashing the 'main' phone ROM. The Hero (as with other Android phones) actually has several partitions (sections) of ROM memory -
1) The recovery image (this is what the Anon_RA image overwrites) installs software which allows you to easily load in other ROMs, backup your current phone (Nandroid), or restore from backups. There are also other tools here for setting up your SD card to work with some of the custom ROMs more easily. Overwriting the recovery image does not erase your personal data or apps.
2) 'Main' phone ROM - ie, the software you see when your phone boots up normally. This is what the MoDaCo ROM and other custom software overwrites. Usually, overwriting this ROM memory will erase your data. This is why it's imperitive that you create a backup before flashing one of these images.
The MoDaCo ROM is 'special' in that it's a no-wipe ROM - which means theoretically it should not overwrite your apps or personal data. This ROM installs custom software over the top of the /system partition (where the operating system files are stored) without touching your /data partition (where all your apps are stored)
You can safely follow all the steps through flashing the 'recovery' image without harming your phone (in most cases, there is no guarantee). Once that is in place, you'll have the ability to create a backup image of your phone. This is the 'Nandroid v2.2 backup' option in the screenshot earlier in this thread. This will create a 'nandroid' folder on your SD card with images of the entire phone memory, including all your apps and preferences.
|