Ventoy: Create bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI Files • Hacker News Board

Re: Ventoy: Create bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI Files

#121

Post by franga2000 » Fri, Oct 31, 2025, 7:49 PM UTC

chenxiaolong wrote: post #120

franga2000 wrote: post #68

Ventoy is great, but what I really miss is DriveDroid from the good old days. It still exists, but it's not quite as reliable on modern Android as it was on rooted Cyanogenmod back in the day and the distro download links have rotten away. For those not familiar with it, it turns your Android phone into a USB DVD drive, meaning not only can you just download and host any distro with a few taps, you also don't need an…

I wrote https://github.com/chenxiaolong/MSD for exactly that. It's a small wrapper around the Linux kernel's mass storage emulation support (CONFIG_USB_CONFIGFS_MASS_STORAGE). It can emulate a read-only optical drive, a readable disk, or a writable disk. It is compatible with both older devices that configure USB via init scripts and newer devices that use Android's USB gadget HAL, but it does require Android 11+.

Looks cool, bookmarking for when I finally have a rooted phone again

Re: Ventoy: Create bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI Files

#122

Post by anonymousiam » Sat, Nov 01, 2025, 9:57 AM UTC

fuzzfactor wrote: post #114

anonymousiam wrote: post #67

Ventoy is cool and I've used it to boot many different operating systems. The one OS that I've had issues with is FreeDOS. Ventoy will boot it, but I've been unable to access any media on the target system. I'd like to be able to access a separate USB drive, or a hard disk. Maybe there's some trick to doing this that I'm unaware of...

Booting to DOS you have to plug in other target drives before you power up so the BIOS will recognize them first before DOS boots. Also DOS will not recognize files on anything but well-tempered FAT32 volumes usually, and the drive device needs to be MBR layout, not GPT. Plus the motherboard needs to support legacy CSM and have it enabled unless it's an old native-BIOS-only non-UEFI PC.

If I boot FreeDOS without Ventoy, I can access and use the filesystems. If I boot it with Ventoy, I cannot access them. I believe Ventoy adds hooks to remap things so it can boot as though from a CD, but once booted, FreeDOS doesn't unmap, because it's using the BIOS.

Re: Ventoy: Create bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI Files

#123

Post by fuzzfactor » Sat, Nov 01, 2025, 7:50 PM UTC

anonymousiam wrote: post #122

fuzzfactor wrote: post #114

Earlier quoted context omitted.

Booting to DOS you have to plug in other target drives before you power up so the BIOS will recognize them first before DOS boots. Also DOS will not recognize files on anything but well-tempered FAT32 volumes usually, and the drive device needs to be MBR layout, not GPT. Plus the motherboard needs to support legacy CSM and have it enabled unless it's an old native-BIOS-only non-UEFI PC.

If I boot FreeDOS without Ventoy, I can access and use the filesystems. If I boot it with Ventoy, I cannot access them. I believe Ventoy adds hooks to remap things so it can boot as though from a CD, but once booted, FreeDOS doesn't unmap, because it's using the BIOS.

Interesting observation, thanks for adding that.

If you're using the FreeDOS ISO in Ventoy, maybe replacing it with a FreeDOS IMG that is a bitwise copy of a working "floppy" image would be a workaround?

Or add a second partition on your Ventoy stick for FreeDOS to occupy on its own and choose it like bare metal dual-boot style?

I actually still put MS-DOS on some sticks [0], haven't used FreeDOS in a number of years, but either way I do prefer for the stick to have a partition table and resemble a HDD, rather than the simpler non-partitioned floppy-simulating layout, even when they both work.

[0] People are still not disappointed by Tetris :)

Re: Ventoy: Create bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI Files

#124

Post by fuzzfactor » Sat, Nov 01, 2025, 8:05 PM UTC

munchlax wrote: post #101

bombcar wrote: post #95

Earlier quoted context omitted.

ChatMBR.

I've replaced all my GPT disklabels with Sun disklabels because I refuse to let them talk. UEFI still boots. Spec said it can boot from fat in an eltorito floppy image and sun disklabels sit in the second or so sector. Spec also said it abstracts the type of volume so all boot methods always work for all drives. ISO images don't use the first 4kB so it doesn't see there's disklabel at all So now I can mount the ssd a…

I love this example.

This is pretty advanced, and who knows if anybody else is doing it exactly like this or not, but it is exactly what the hardware is supposed to be easily capable of, just as easily as what the vast mainstream users are getting out of the hardware by "default".

This type versatile performance is built-in just like the mainstream arrangement is built-in, the thing is you have to figure it out for yourself through the complex web of capabilities that have been long bypassed in order to make the default experience seem like it is actually simpler or more reliable, when it is not.