For those of you that are having issues with updating to EB13 because of one click root deleting the Asphalt Demo, I have found the solution. I had the same problem. When trying to update via CWM I would get an error message saying the Asphalt demo was missing from the system apps folder.
To get around this, you'll need root access the preloaded asphalt demo, and root explorer.
1) Download the asphalt demo pulled from the stock D18 rom.
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2) Place the file onto your sd card.
3) open root explorer, press the "Mount R/W"
4) find the asphalt file, long press and hit copy.
5) use the back key and find the system folder.
6) within the system folder, find the app folder.
7) once inside the app folder, press the paste button.
8) reboot into CWM
9) now retry updating with your update.zip via clockworkmod and enjoy froyo!
Note: If you get errors regarding the playlogo while trying to update in cwm, reboot and remove the oneclickroot after all these steps. here is the uninstaller noobnl and firon from xda provided: http://firon.net/xda/one.click.stock...aller-di18.zip
Updating does remove OneClickRoot so you will need to reinstall after updating. Hope this helps everyone!