I digged a little bit around and I guess copying the contents of the folder would work. Be sure to copy all the files, specially the status files in the /Download folder too (which are something like WindowsStoreSetupBox.exe and 9600.16415.winblue_refresh.130928-2229_woafre_client_CoreARM_O15_gdr_en-gb-IR1_CCSA_WOAFRER_EN-GB_ESD (depending on region it may change).
Check this, seems to have worked for some people. Jump to the Bob Sled's answer (I don't know how to link to the answer itself in that forum).
About the quiet installation, I'm not sure if you can do that, you can try it of course, wouldn't hurt. If it doesn't accept quiet argument it should just ignore and install normally. Also, using that method in the link, you will update using the Store normally, but since the files are already there it will not bother to download again, and should proceed to the installation procedures.
Here is the answer Bob Sled gave:
After digging around and playing with the generic 8.1 RT install ISO, I've found the easiest method so far, but unfortunately it still is manual via the Store.
Open the Store and start downloading the 8.1 RT update.
Navigate to
C:\Windows\SoftwareDistribution\Download\05013d5dcc65111d54b5456297dbdfad Monitor the disk write activity via Resource Manager and sort by write per interval. Mine was relatively close to my pipe's download speed.
When the disk write drops off, you should have three files in the SoftwareDistribution download folder; a status file, WindowsStoreSetupBox.exe and 9600.16415.winblue_refresh.130928-2229_woafre_client_CoreARM_O15_gdr_en-gb-IR1_CCSA_WOAFRER_EN-GB_ESD (depending on region)
Copy the whole '05013d5dcc65111d54b5456297dbdfad' folder to a temporary location; I'd advise a pen drive or removable HDD.
After this, all you have to do is copy that GUID' folder to C:\Windows\SoftwareDistribution\Download on any other RT device you'd like to update.
Then run the update through the store and it should find the cached files... (you may get a once-off error but just retry).
We have 450 devices to update but this saves us a massive amount of bandwidth and waiting time. Here's a batch file I threw together to save a few clicks (literally); you can't run it under the built-in Administrator account due to MS' security restrictions but you do need to run as admin.
*@echo off echo Enabling Windows Store reg add HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsStore /v RemoveWindowsStore /t REG_DWORD /d 0 /f echo --- echo Copying Windows 8.1 upgrade xcopy "D:\05013d5dcc65111d54b5456297dbdfad" "C:\Windows\SoftwareDistribution\Download\05013d5dcc65111d54b5456297dbdfad" /E /I /H /R /Y xcopy "E:\05013d5dcc65111d54b5456297dbdfad" "C:\Windows\SoftwareDistribution\Download\05013d5dcc65111d54b5456297dbdfad" /E /I /H /R /Y echo --- echo Launching Store "C:\Program Files\Internet Explorer\iexplore.exe" ms-windows-store:WindowsUpgrade* I've added a redundant file copy to counter a drive letter change due to devices which have SD cards or had them in the past. Windows Store is also disabled on our devices so I've enabled it before I attempt to launch the store.