If you’re running a custom ROM, such as Cyanogen Mod 6.1, you have most likely noticed that when you’re looking to update an application you may get a “download unsuccessful” error after the loading bar. The cause of this “bug” (which is not necessarily unintentional) is that some applications your trying to upgrade are already built into the ROMs, therefore already on your phone. Another reason is plain old performance. Most ROMs are designed to push your phone to its limits, and make it as fast as possible. Some apps, as you already know, can decrease performance.
So you still want to update your app? Okay. MrPicolas decided to put all this information in a great, organized instruction list. Follow the instructions, and carefully decide which path to follow to suit what you need to do.
Important) Please read the following: 3rd party themed..
apps that are not in system/app folder will update as usual and you will lose the themeing of that app. I know that sounds like a pain, but there is a quick fix in case this happens to you. A simple uninstall of the update through the market should revert you to your themed app. To keep this from happening again make sure to uncheck the auto update box for your app.
Here are the steps to update pre-installed apps that will not update:
*For rooted phones only
*Droid life is not responsible for damages,acts of god and loss of spouses due to messing with your phone.
1. You need a file manager that gives you read write access to the system/app folder. Root Explorer is a great choice for this.
2. You need to locate the app you want to update in system/app. Once you find it you need to enable R/W (read-write) in Root Explorer. It is set at R/O (read-only) by default and by doing this, it will let you delete or move the app from your system folder. I suggest moving it out from system/app and onto somewhere safe like your SD card. You can also just rename the app to end with .bak if you don’t want to move it.
3. Now head out to the market and find the app you wanted to update, install like normal and enjoy your newly updated app.