It so happens that I need to install Win7 on a PC with a brand new blank HDD (the old one failed). I have the needed .iso file (on my Android tablet) and the only place I can stuff a USB flash into is my ASUS router ;) I presumed that if I simply telnet into my router (the .iso is on another flash) and perform

umount /dev/sdc
dd if=ru_windows_7_home_premium_with_sp1_x64_dvd_u_676728.iso of=/dev/sdc

then it should create an exact copy of the iso with MBR and all, regardless of what OS is there. But no such luck: after dd completes (it takes quite a while) the USB is unbootable and unreadable. What am I doing (or thinking) wrong?

  • 1
    Remember that while your bios might be able to boot any media it likes (USB, CD, HDD) the thing installed on that media (windows installer) also needs the right drivers in all the right places to read from the media. If the windows bootloader is intended for a CD, it might not understand what a USB stick is. Feb 18, 2019 at 14:25
  • I like the idea of installing Gnu/Linux, and Virtual Box, and putting MS-Windows in the box. It is easier, and safer. Feb 18, 2019 at 20:06

2 Answers 2


There are strange dependencies between file-systems, and storage media, in both MS-Windows, and PC firmware boot-loaders.

ISO images are for CDs, not usb-storage. Some ISO images are hybrid, but not all.

  • As for file systems, I presumed that dd would write on a lower level, wiping out whatever file system was there before and creating the whatever file system is part of the iso file. Your second point must be the reason - the problem is I have no idea how to check or make it "hybrid". There are articles on creating Win7 bootable flash drives on Linux, they all involve custom GUI software that obviously won't run on my router... Apparently this software exists for a reason and there is no easy way.
    – Marassa
    Feb 18, 2019 at 14:21
  • ISO 9660, is a file-system, for CDs en.wikipedia.org/wiki/ISO_9660 Feb 18, 2019 at 20:04

1> make your thumb-drive a linux-live drive (same procedure you said before)
2> boot your computer from that live linux
3> use your PC disk drive to burn 'windows' ISO onto a DVD
4> restart your pc with DVD in

Or easier:

1> Call a friend and ask to use his pc to burn your 'windows' dvd
2> start your pc with new dvd in
3> launch windows setup
4> offer a beer (or some vodka) to your friend and enjoy
5> reboot your PC

1> Make a 'live linux usb' (same as 1st way)
2> Install linux on your pc
3> Install Virtualbox
4> Install windows into virtual machine

  • Wow, that sounds brilliant - I'm off to google up "linux-live" and where to get one ;)
    – Marassa
    Feb 18, 2019 at 14:24
  • I would have used the "easier" way if I were not down with a flu ;) Don't really want to leave home with a fever.
    – Marassa
    Feb 18, 2019 at 14:27
  • Get well soon! 123
    – DDS
    Feb 18, 2019 at 14:34
  • Must be still doing something wrong - got a Slax .iso (first to come up in search), used the same dd command (took much less time as Slax is much smaller than Windows) but still the PC won't boot off it and the router won't mount it..
    – Marassa
    Feb 18, 2019 at 14:53
  • dd bs=4M if=input.iso of=/dev/sdc conv=fdatasync Also check the distro you downloaded is UEFI-compatible
    – DDS
    Feb 18, 2019 at 14:55

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