You can use multiboot usb to set up multiple distro live images on one usb drive: https://aur.archlinux.org/packages/multibootusb/ I've used it, it works well. Looks like there's a build issue at the moment, but in general it works :p On Tue., 5 Nov. 2019, 22:50 Hongyi Zhao via arch-general, < arch-general@xxxxxxxxxxxxx> wrote: > brent s. <bts@xxxxxxxxxxxxxxx> 于2019年11月6日周三 上午10:42写道： > > > > On 11/5/19 9:11 PM, Hongyi Zhao via arch-general wrote: > > >>> $ sudo ddrescue -f archlinux-2019.11.01-x86_64.iso /dev/sdc2 > > >> The ISO contains multiple partitions, so probably not. > > > > > > Why when using the whole usb disk, the problem will disappear? > > > > > > > As both Eli and I have both explained, because if you use the whole disk > > you're writing a partition table as *the partition table for the > > device*. If you try to write to a partition, you end up with nested > > partition tables. The .iso file is a *disk image*, not a *partition > image*. > > > > >> Why are you > > >> trying to do this, precisely? > > > > > > I want to use a usb disk for installation of multiple distros, say, > > > Debian, Ubuntu, Arch, and so on. > > > In this case, I must not using the whole usb disk for only one iso, > > > and on the other hand, using whole usb disk for only one iso, is > > > wasting of the usb's space, considering that we cannot use it for > > > doing other things. Furthermore, I noticed that the dd-based method > > > is more robust than using the iso directly with grub's loopback > > > module. > > > > In what way? I do not agree with this. It's far easier to update the > > ISO, it's far easier to add new distributions to the bootloader (and > > both updating and adding new entries can even be done by regular users > > without granting disk reformatting permissions), etc. with grub loopback. > > > > > To say the least, for the Debian iso, the dd-based method can do the > > > trick while the loopback method will fail to detect the cd-rom during > > > the installation progress. > > > > Are you using the appropriate kernel cmdline args in the menu entry? > > They're different from Arch's grub loopback menu entry. > > This is just what I stucked on. I failed to figure out the correct > cmdline args used for linux and initrd. > > > > > https://wiki.debian.org/DebianLive/MultibootISO > > Useless. This is for Debian *live* instead of Debian *install* iso, > the image I use for install Debian is: > > > http://mirrors.ustc.edu.cn/debian-cd/10.1.0/amd64/iso-dvd/debian-10.1.0-amd64-DVD-1.iso > > > > > > > > > > >> > > >> Alternatively, you can use grub to boot an ISO *file* as a loopback > > >> device. Some people do this to create multiboot USBs. > > > > > > As I said above, this method is not so robust as the dd-based method. > > > In detail, the most robust method for using the usb disk to > > > installation a unix/linux OS, should be the dd-based method which > > > using the whole usb disk. But this method has the shortcoming that it > > > will occupy the whole usb disk with only a small iso image and > > > prohibit us for using the usb disk to do other things at the same > > > time. > > > > This seems highly subjective. What makes using DD superior to a > > loopback? It occupies the same exact disk space as if you dd'd to a > > partition except requires no modifications to the host disk. > > > > Now, if you *really* want to save space, you'd extract the squashed > > filesystems/initrds/kernels from each ISO you want to add and create > > grub entries that boot those directly, but that only affords you a > > couple extra megabytes per distribution. However, *that is not what grub > > loopback is*. Grub boots an iso file *directly*, with no modifications > > required. I guarantee it's far more maintainable and robust than any use > > of dd. > > > > -- > > brent saner > > https://square-r00t.net/ > > GPG info: https://square-r00t.net/gpg-info > > > > > -- > Hongsheng Zhao <hongyi.zhao@xxxxxxxxx> > Institute of Semiconductors, Chinese Academy of Sciences > GnuPG DSA: 0xD108493 >
