Re: Cannot boot from emulated usb key if machine contains an emualted hard disk

[Thomas Huth]

On 17/05/2021 22.10, Paul Dufresne wrote:
> If I do:
> qemu-system-i386 -m 64M -drive node-name=erika,file=FD13FULL.img,format=raw 
> -usb -device usb-storage,drive=erika
> I get:
> qemu-system-i386: -device usb-storage,drive=erika: Conflicts with use by 
> ide0-hd0 as 'root', which does not allow 'write' on erika
>
> I am able to boot from my emulated usb key (as if it is an hard drive) by doing:
> qemu-system-i386 -m 64M -blockdev 
> node-name=erika,driver=file,filename=FD13FULL.img -usb -device 
> usb-storage,drive=erika
>
> If I do:
> qemu-system-i386 -m 64M -blockdev 
> node-name=erika,driver=file,filename=FD13FULL.img -usb -device 
> usb-storage,drive=erika -drive file=hd.img,format=raw
> boot failed, not a bootable disk... I think because it try to boot from 
> hd.img, which is a freshly created disk image (so with no system yet).
>
> I may try to change index:
> qemu-system-i386 -m 64M -blockdev 
> node-name=erika,driver=file,filename=FD13FULL.img -usb -device 
> usb-storage,drive=erika -drive file=hd.img,format=raw,index=3
> Same error: boot failed, not a bootable disk

To specify a boot priority, the right parameter is called "bootindex", and 
you should it attach to the usb-storage device, e.g.:

 ... -device usb-storage,drive=erika,bootindex=1 ....

I hope that helps!

 Thomas