Use the Windows 7 USB/DVD Download Tool with custom ISOs
While Paul Thurrott was playing with the official Windows 7 USB/DVD Download Tool, creating a bootable USB stick for his netbook upgrade, he ran into an interesting snag with certain discs. The tool, when directed to use an ISO dumped via ImgBurn, would error out. Everything was to UDF spec, so what was going on here?
I’m not a UDF expert, hell not even a novice, but I skimmed through ECMA-167 and the reflected tool code. It appears there are two (possibly more) “navigation buoys” within UDF-formatted ISOs that point to important chunks of the image called Anchor Volume Descriptor Pointers (AVDPs). The first AVDP is somewhere near the top of the image. The last AVDP is located in what appears to be the last logical block of the image. (My guess is this is to support bi-directional reading.)
So assuming each logical block of the image is 2048 bytes large, one could also assume the last logical block is –2048 from the end of the file, right? Well, that’s what the tool assumes. It checks for the last AVDP at the start of the last logical block, doesn’t find it, and bombs out.
I haven’t read through the entire spec., but I doubt there’s anything in here regarding the container of the UDF formatted data.
While one could argue Microsoft Store-downloaded ISOs are comprised in a compatible manner and therefore this scenario is unsupported it wouldn’t have been hard to add some AVDP seeking code.
As a quick hack to resolve this issue, I wrote a tool that merely finds the AVDP in your ISO file and copies it to offset (EOF-2048). This will allow you to use your own ISOs with the Microsoft tool. Microsoft.NET 2.x or higher required.

What do you do if the ‘custom’ .iso is somehow marked ‘read only’? File->Properties does NOT list it as R/O?
Is the file open in another tool? Do you have the proper permissions?
Not open in any other tool. ‘attrib’ shows only the archive bit set.
Hi, I am regular reader of your blog. Please I insist you, If you can change some code in “Windows 7 USB/DVD Download Tool” so we can burn Windows XP and Windows Vista original and customs ISOs.
Yours faithful reader
Zulali Khan
An other way to create a bootable USB drive to install W7 from is:
Format the drive from a Vista/W7 machine:
CMD
FORMAT F: /FS NTFS (where F: is of course your USB drive)
Activate the first partition on tht drive:
Start DISKPART
LIST DISK
SELECT DISK x (where x is the drivenumber shown from the previous command)
SELECT PARTITION 1
ACTIVE
EXIT
Mount your newly downloaded ISO from Microsoft with Daemon tools or other mount-tool
Place a W7 bootsector on the drive:
Z: (where Z: is your cdrom drive where the ISO is mounted)
CD \BOOT
BOOTSECT /NT60 F:
Now copy all of the files of the mounted cdrom to the USB drive
XCOPY Z:\ F:\ /S/E
Now boot from the USB drive to install W7!
It would be great if you could use the text of the error message as the ALT text to the image so it could be properly indexed by the search engines. I’m sure this page could be very helpful to many people if they can find it. Love your site; wish you’d post more often.
Another insightful little piece from Rafael, combined with a convenient tool to fix the addressed problem. I tip my hat to you sir.
USE UltraISO 9 !!!
1. Simply insert your USB pen.
2. Open any win XP, Vista or Windows 7 ISO in UtraISO,
3. Select “Bootable” and “Write Disk Image”.
REMEMBER to double check the drive letter ;-)
Thats it !!
And it also works on USB disks etc.
Windows 7 installs in 7 minutes.
Zulali Khan: Rafael is not in any way involved with the Windows 7 USB/DVD Download Tool so he can’t do what you asked.
You can try doing it by hand, though. You would need to copy all the files from the DVD to a blank USB thumb drive, and then copy the bootloader. Then whatever computer that you wanted to boot from would need to use “USB-CD” as the boot type, since the bootloader is for a CD. I’m not an expert but that SHOULD work. However Windows XP/Vista setup may not function properly even if it does start up right; it’s possible that Windows 7 Setup had specific code changes to support installing from a USB drive, and that since XP/Vista were not made for it they simply might not work.
However it can’t hurt to try.
Arnie: You should use FAT32 instead of NTFS for flash drives. FAT32 has less overhead as far as space used and speed of transfer AFAIK. In addition most of the features of NTFS over FAT32 aren’t very useful for thumb drives.
ok I have an iso of windows 7 then i run this tool it says copied then i run the microsoft tool it still says not valid iso .. Nero or any other tool will allow me to burn as bootable dvd and it installs fine please tell me what step I am missing….
Dave
19 years after Windows 95, Microsoft is up to the same lock down tactics. And yet people fall for them like anything.
Um @anon, explain how this is a lock down tactic? This tool is documented and supplied by Microsoft as a tool to burn your copy of Windows 7 which you bought from the Microsoft Store, not one you created yourself/bought elsewhere. It serves its purpose, it does not promise anything it can’t do, I don’t see the “lock-down” problem.
That aside, thanks Rafael, I have a custom ISO made from the Student Offer upgrade thing and this worked a treat :D
Please go over procedure touse my custom iso with this tool then resave the image then use microsofts tool.Thanks,
Dave
Tested it on 2 different images.
Both completed succesfull and both are not usable in the Windows 7 USB/DVD Download Tool.
gee at least I am not alone on that this tool does not work..
What did you create these ISOs with? This isn’t a cure all for broken ISOs…
the iso themseleves work fine ..made with power iso
I created a custom ISO using oscdimg from the WAIK. The ISO I created was compatible with the Windows 7 USB Download Tool. Here is the command I used:
oscdimg -lWindows_7 -u2 -bC:\DVD_Data\Boot\etfsboot.com C:\DVD_Data C:\Win7.iso
An explanation of how to use oscdimg is here: http://technet.microsoft.com/en-us/library/cc749036%28WS.10%29.aspx
Thanks for the right answer, techie. I created my ISO with the same tool you did. My only mistake was assuming “-?” would give all the switches….it doesn’t!
Thanks samoht Coulter, it worked!
nice bandaid but it does not address taking an iso made using custom settings etc for use with image deployment using the microsoft tool is there another tool that takes the iso and performs the same magic?
It seems that Microsoft has changed the URL of the tool. Link from your post is not working.
Tool is b*llshit.
The Windows 7 USB/DVD Download Tool has been pulled from the Microsoft Store. The link to it (http://store.microsoft.com/Help/ISO-Tool) now returns “Sorry, the page you are looking for cannot be found.” Evidently the tool violated the GNU’s General Public License (GPL) for using open source code —
http://arstechnica.com/microsoft/news/2009/11/microsoft-pulls-windows-7-tool-after-gpl-violation-claims.ars
I downloaded Windows 7 from the online shop (working in a college I got it for £30) I then used the Windows Automated Installation Kit to create a bootable iso that can be burnt onto DVD with any software. I used Image Burn and also use Magic ISO (both are free!). Although now having Windows 7 I have build it iso burning support :)