Peppermint 6 linux CD boots normally if put in an external USB CD drive.

But not if put in the internal CD drive of the same computer. It appears in the BIOS list when you press F12, you can select it, but the system boots off the hard disk instead.

This does not happen with the windows 7 or acronis bootable CD. These boot normally, whether in the internal or the external drive.

How can this be?

Here are the relevant sections of the output of lshw:

Internal drive:
*-scsi:1
physical id: 2
logical name: scsi1
capabilities: emulated
*-cdrom
description: DVD-RAM writer
product: DVD-RAM UJ8E2
vendor: MATSHITA
physical id: 0.0.0
bus info: scsi@1:0.0.0
logical name: /dev/cdrom
logical name: /dev/sr0
version: 1.00
capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
configuration: ansiversion=5 status=nodisc

External drive:
*-scsi:4
physical id: 5
bus info: usb@3:4
logical name: scsi6
capabilities: emulated scsi-host
configuration: driver=usb-storage
*-cdrom
description: DVD-RAM writer
product: CD/DVDW SH-S182M
vendor: TSSTcorp
physical id: 0.0.0
bus info: scsi@6:0.0.0
logical name: /dev/sr1
logical name: /cdrom
version: SB05
capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
configuration: mount.fstype=iso9660 mount.options=ro,noatime state=mounted status=ready
*-medium
physical id: 0
logical name: /dev/sr1
logical name: /cdrom
capabilities: partitioned partitioned:dos
configuration: mount.fstype=iso9660 mount.options=ro,noatime signature=466a2298 state=mounted
*-volume UNCLAIMED
description: Windows FAT volume
vendor: mkfs.fat
physical id: 2
version: FAT12
serial: 20e8-7ecd
size: 15EiB
capabilities: primary boot fat initialized
configuration: FATs=2 filesystem=fat

Some readers will not like some burns of linux. Generally you have to try best quality CD/DVD's and burn at the very slowest speed you can. Even that sometimes doesn't work.

To test, I'd buy one of those black cd disc's and burn it at slowest speeds.

However some readers just are out whack just enough that a cd won't boot.

I don't think it is an issue of a boot time switch as in the case of some Knoppix cd's a log time ago.

Could be that your reader doesn't fully support overburn or some oddity of the disc's you are using.

Just tried another dvd from another manufacturer, and burnt it at the slowest speed. It still does not boot.

Tried giving the dvd drive to a vmware VM as a physical disk. It boots alright.

Tried specifying firmware="efi" in the vmx. It works just as well, the only difference is the EFI setup replaces the BIOS setup.

Have we therefore ruled out physical problems with the DVD drive or DVD?

The physical system has Secure Boot enabled. And does not allow you to disable it in an obvious manner. Why would it treat the internal DVD drive differently from the USB one for booting purposes?

I'd boot to F key menu and see if one of the choices are uefi boot from internal disc drive. Some bios's will let you select the type of bootable choice. Like uefi cd versus legacy cd or some such names. May have to go into second menu for either legacy or uefi boot choices. That has nothing to do with secure boot however it has to to with uefi boot I'd think.

I guess it still could be how the disc is being read differently on usb but from your report it may be more to do with how the device is reporting the disc to the bios. Could be that the usb is being selected as a uefi boot by default in bios. Might have something to do with how they made the distro. It would be a hybrid iso and may have some feature that makes it usb choice uefi.

Uefi has not played well with me so far.


If your system let's you then you have to go into bios and select the secure boot but it too isn't sometimes easy. You may have to look for an odd name to select it. May have to install keys if you want to use secure boot.

Guess you could try the latest LTS ubuntu or maybe the updated 14 version to see if that boots correctly. I've had the best luck with it on secure boot systems so far. This would be simply a test of system but it is a fully usable system.