don40
August 16th, 2015, 10:19 PM
Hi,
I have multi-boot system with Windows 7 on one drive and Ubuntu on another. This was working fine until I upgraded from Ubuntu 14.10 to 15.04 about a week ago. Now, every time I boot Ubuntu from my hard drive, it writes 4 KB of apparently random data to the beginning of my Windows drive. The next time I try to boot Windows, I get error 0xc000000f: "The boot selection failed because a required device is inaccessible."
http://i.imgur.com/qBOavPD.png
However, this doesn't happen when I boot Ubuntu 15.04 from a USB drive.
Here's the output of boot-info while everything is working (i.e., after I restored my Windows drive):
http://paste.ubuntu.com/12100956/
And here it is after booting Ubuntu, then rebooting from the login screen without ever logging in:
http://paste.ubuntu.com/12101036/
For reference, the drives listed in the boot-info output are:
/dev/sda1: 100MB Windows 7 system partition
/dev/sda2: Main Windows 7 partition
/dev/sdb1: An older Windows 7 partition that I rarely use anymore. It seems unaffected.
/dev/sdb2: Linux swap
/dev/sdb3: Main Ubuntu 15.04 partition
/dev/sdc1: ext4 storage drive
/dev/sdd1: Ubuntu 15.04 USB drive (FAT) that I used to generate the boot-info output.
/dev/sde1: Another USB drive (FAT) that I used for persistent storage while diagnosing the problem
You'll notice that in the first boot-info output, the /dev/sda2 hexdump shows a valid NTFS header, but in the second boot-info output, it says "Unknown bootloader on sda2" and the hexdump looks random.
I should probably mention that I have grub installed on /dev/sdb. Before I got my newer Windows 7 drive, I would dual boot between Windows 7 on /dev/sdb1 and Ubuntu on /dev/sdb3 (they weren't called "sdb" at the time, of course). Now I just use my BIOS's boot menu to choose between /dev/sda and /dev/sdb. When I select /dev/sdb, I get the grub menu, which has choices for Ubuntu and the older Windows 7 drive that I don't use much anymore.
I tried dumping the first 256 MB of /dev/sda to a file after restoring from a backup, and then again after reproducing the problem. When I compared the two files, there were over 4000 bytes that differed, and all of them were between bytes 105906176 and 105906176 + 4096. (105906176 being the beginning of /dev/sda2 at 101*1024*1024 bytes).
Then I booted Ubuntu a second time and dumped /dev/sda a third time to see if Ubuntu is writing the same 4 KB of data every time, and it's not. All three dumps were different in that same 4 KB block.
Does anyone know what would cause Ubuntu to write data to a Windows drive like this at boot? Thanks in advance!
I have multi-boot system with Windows 7 on one drive and Ubuntu on another. This was working fine until I upgraded from Ubuntu 14.10 to 15.04 about a week ago. Now, every time I boot Ubuntu from my hard drive, it writes 4 KB of apparently random data to the beginning of my Windows drive. The next time I try to boot Windows, I get error 0xc000000f: "The boot selection failed because a required device is inaccessible."
http://i.imgur.com/qBOavPD.png
However, this doesn't happen when I boot Ubuntu 15.04 from a USB drive.
Here's the output of boot-info while everything is working (i.e., after I restored my Windows drive):
http://paste.ubuntu.com/12100956/
And here it is after booting Ubuntu, then rebooting from the login screen without ever logging in:
http://paste.ubuntu.com/12101036/
For reference, the drives listed in the boot-info output are:
/dev/sda1: 100MB Windows 7 system partition
/dev/sda2: Main Windows 7 partition
/dev/sdb1: An older Windows 7 partition that I rarely use anymore. It seems unaffected.
/dev/sdb2: Linux swap
/dev/sdb3: Main Ubuntu 15.04 partition
/dev/sdc1: ext4 storage drive
/dev/sdd1: Ubuntu 15.04 USB drive (FAT) that I used to generate the boot-info output.
/dev/sde1: Another USB drive (FAT) that I used for persistent storage while diagnosing the problem
You'll notice that in the first boot-info output, the /dev/sda2 hexdump shows a valid NTFS header, but in the second boot-info output, it says "Unknown bootloader on sda2" and the hexdump looks random.
I should probably mention that I have grub installed on /dev/sdb. Before I got my newer Windows 7 drive, I would dual boot between Windows 7 on /dev/sdb1 and Ubuntu on /dev/sdb3 (they weren't called "sdb" at the time, of course). Now I just use my BIOS's boot menu to choose between /dev/sda and /dev/sdb. When I select /dev/sdb, I get the grub menu, which has choices for Ubuntu and the older Windows 7 drive that I don't use much anymore.
I tried dumping the first 256 MB of /dev/sda to a file after restoring from a backup, and then again after reproducing the problem. When I compared the two files, there were over 4000 bytes that differed, and all of them were between bytes 105906176 and 105906176 + 4096. (105906176 being the beginning of /dev/sda2 at 101*1024*1024 bytes).
Then I booted Ubuntu a second time and dumped /dev/sda a third time to see if Ubuntu is writing the same 4 KB of data every time, and it's not. All three dumps were different in that same 4 KB block.
Does anyone know what would cause Ubuntu to write data to a Windows drive like this at boot? Thanks in advance!