Only system.img is updated. The contents of userdata.img is by definition the user's data, and if you replace it you replace the user's data. You don't include it as part of an update, and you don't put anything you want to be able to update in it. Typically the stock device images has a basically empty user data.
On Thu, Oct 8, 2009 at 10:07 AM, Mr. INTJ <[email protected]> wrote: > > Hi, > > I'm trying to understand what happens under the covers when *end- > users* upgrade their device firmware from Android ver. X to X+1 > (regardless of whether they initiate the action, or their carrier > sends the update OTA). > > I'm working on an Android based device, and I need to understand how > this is supposed to work. A new build of Android contains system.img > and userdata.img (among other files). The system.img file is read- > only, so replacing the user's existing copy shouldn't result in any > data loss. Not so with userdata.img; overwriting this file with a > newer version would destroy all of an end-users application data > (wouldn't it?). Could it be that userdata.img never contains any data > that needs to be updated during a FW upgrade, and so isn't > overwritten? Or is there some process that merges changes into /data? > > Surely there is a procedure envisioned for upgrading FW for Android- > based devices without nuking users' address books, and other private > data. Unfortunately, Googling for this information yields only pages > containing specific hacker-level instructions (e.g. adb commands); I > can't find any mention of this topic online, or in the documentation. > > > > Does anyone know how this is supposed to work, or where this is > documented? > > Thanks very much in advance. > > -Mr INTJ > > > > -- Dianne Hackborn Android framework engineer [email protected] Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. --~--~---------~--~----~------------~-------~--~----~ unsubscribe: [email protected] website: http://groups.google.com/group/android-porting -~----------~----~----~----~------~----~------~--~---
