[Expired for QEMU because there has been no activity for 60 days.] ** Changed in: qemu Status: Incomplete => Expired
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1854878 Title: Physical USB thumbdrive treated as read-only Status in QEMU: Expired Bug description: So I have installed FreeDOS on my USB thumbdrive, by using Rufus. Everything goes as expected so far. That's good. When I run QEMU with this command line: qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1 it of course is read-only, just like the resulting console message says: WARNING: Image format was not specified for '\\.\PhysicalDrive1' and probing guessed raw. Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted. Specify the 'raw' format explicitly to remove the restrictions. So what I then did, was I ran QEMU with this command line: qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1,format=raw As expected, the above mentioned console message no longer appears. However, beyond that, QEMU doesn't behave as it should regarding read-only status. When I try any operation that involves writing to the drive, it becomes quite clear that the drive is still read-only. Any writing operations to the drive result in FreeDOS giving me the error message: Error writing to drive C: DOS area: sector not found. The above situation is clearly a bug. QEMU should not be treating it as read-only once I specify format=raw. Note that drive C is how the guest OS refers to the USB thumbdrive (it's drive E in my host OS, and drive C in my host OS is the actual system drive). And yes, it is a QEMU bug. It's not a FreeDOS bug I tested it with this command line, so that all changes would be written to a temporary snapshot file: qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1,format=raw,snapshot That last drive option "snapshot" tells QEMU to create a temporary snapshot file, and to write all changes to that. When I do that, all write operations are successful. So it seems that there is a bug in QEMU where it keeps read-only mode in place for a physical drive, even when format=raw is specified. Please fix this bug. Thanks in advance. Here's my current setup. Host OS: Windows 10 (64bit) Guest OS: FreeDOS QEMU version: 4.1.0 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1854878/+subscriptions