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Author Topic: ISOHYBRID solves DD woes!  (Read 3492 times)

Offline PDP-8

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ISOHYBRID solves DD woes!
« on: August 16, 2020, 02:29:17 PM »
Apparently, I didn't get the memo on this.  It's in here somewhere .. :)

If you are trying to burn the release iso's, and they don't work on modern machines with simple DD or other gui burners, typically ending up at the grub prompt, try this:

Add some ISOHYBRID spice to the iso before you burn.  In my case, on a very modern machine, I did this:

sudo isohybrid <path/to/your/iso>

In my case, on an ultra modern little hockey-puck mini-pc, added the --uefi component

Code: [Select]
sudo isohybrid --uefi TinyCorePure64-11.1.iso
Now a bootable stick can be made from either DD, or other 3rd party burning utilities, that mostly do dd internally anyway.  They are just following directions to the letter, but if the iso doesn't have the isohybrid spice on it, then tears follow.

Note that when burned to stick, this of course results in what appears to be the "CD" read-only type of operation, so you'll want to resort to other measures to build a stick on a different writable /bootable filesystem.

OR, use as is, and enter kernel cheatcodes manually all the time if needed.  Like a cd-environment, you can at least set up persistence by using things like tce-setdrive and following the rest of the usual stuff for TC to go further.

This explains the chicken-and-egg phenomena if you only have a windows box, or even chromebook (using the restoration trick), you don't have any way to ISOHYBRID the iso before burning.  The obvious thing to do is get another distro bootable, download the tinycore iso, and isohybrid it from there.

When that dd'ed  stick came up on my uefi-only box after doing the isohybrid --uefi trick on it, I suddenly knew what a cheshire-cat grin was all about. :)
That's a UNIX book! - cool  -- Garth

Offline hiro

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Re: ISOHYBRID solves DD woes!
« Reply #1 on: August 18, 2020, 01:55:55 AM »
imo would be useful to have that by default in our releases

Offline PDP-8

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Re: ISOHYBRID solves DD woes!
« Reply #2 on: August 18, 2020, 03:25:19 AM »
You'd think so, but I understand why not - and leaving it up to us to determine if we need it or not.

The whole thing about making a cd-type "iso" work on a usb stick, and fool the systems into thinking they are booting hd drives, is like fitting a round peg into a square hole. :)

Not my words, but I think the author of Rufus explains it very well here - and the dangers of over-relying on isohybrid:

https://www.howtogeek.com/291484/why-is-creating-a-bootable-usb-drive-more-complex-than-creating-bootable-cds/

Although the article goes a little bit into the rufus settings, the description about iso-hybrid finally sunk in with me, and why that util offers you 2 ways (iso and dd) and actually now 3 (iso / iso efi / dd).

The issue is that you don't know if the iso authors have left their iso's unmolested, iso-hybrid'ed or what.  You can run the risk of trying to isohybrid an iso that is already isohybrid'ed.

I can kind of even see where over the years when usb sticks became popular to boot from, and the many ways to burn an iso, some of those used to the simpler good-old-days of just burning a cd and getting on with it, could just call it quits and buy a mac.  Or chromebook, or something else.

Kind of like if when Linux became popular, that cd's had to be burned to emulate 9-track mag tapes to boot. :)

Not a super big deal, but we're hanging in there.  Nothing insurmountable.
That's a UNIX book! - cool  -- Garth

Offline curaga

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Re: ISOHYBRID solves DD woes!
« Reply #3 on: August 18, 2020, 09:42:12 AM »
The isohybrid docs say that some Gigabyte uefi bioses are buggy, and fail to boot uefi isos. That makes it not so easy a choice.
The only barriers that can stop you are the ones you create yourself.

Offline hiro

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Re: ISOHYBRID solves DD woes!
« Reply #4 on: August 18, 2020, 12:29:33 PM »
just ignore EFI, this way i don't see the downside, you can just document that it's isohybrid and can be dd'ed to disk and loaded by a compatible BIOS. how exactly the user has to set up their EFI to support legacy disk boot is not part of the scope i think :D

Offline hiro

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Re: ISOHYBRID solves DD woes!
« Reply #5 on: August 18, 2020, 01:38:40 PM »
btw the only thing he seems to say about isohybrid is:

"But of course that means that, whoever created the ISO system must have made some provisions to support FAT32 or NTFS as a file system for live use or installation (which not all people, especially the ones who rely a bit too much on ISOHybrid, tend to do)."

and since we will always ship with fat32 support i don't see any problem at all, apart from that isohybrid kinda makes the point of his rufus tool moot :P

Offline PDP-8

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Re: ISOHYBRID solves DD woes!
« Reply #6 on: August 18, 2020, 05:23:06 PM »
Well, at some point you can't ignore uefi - many modern machines give the user no choice but to use it where csm fallbacks simply aren't there.

Aside from convenience with dd or other tools, if you boot from a stick on these machines, they *have* to emulate an hdd, not an optical cd or they simply won't boot.  Sometimes for technical reasons, and sometime they do it for security - not allowing pesky kids to come along and boot a machine from a usb port and an cd/dvd dongle thingy .. :)

But, there is a hidden gem to Rufus.  Instead of burning isos, one can do it the way nature (and Juanito) intends! :)

You can make a bootable syslinux, grub, or other bootloader stick on a variety of filesystems like ext2/3/4 etc (even though windows won't see it when done) with Rufus, and simply copy the distributable files from the repo onto the stick with a system that does.  Put them in the right directory structure, and write your grub.cfg or extlinux.cfg.

No iso funny business involved!

Anyway, that's the cool thing about TC.  There are ways around most any issue.
That's a UNIX book! - cool  -- Garth

Offline curaga

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Re: ISOHYBRID solves DD woes!
« Reply #7 on: August 19, 2020, 12:15:20 AM »
We have used isohybrid for CorePlus isos for years now. I thought you meant with the uefi option, hiro, since this thread was about uefi.
The only barriers that can stop you are the ones you create yourself.

Offline hiro

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Re: ISOHYBRID solves DD woes!
« Reply #8 on: August 19, 2020, 06:28:16 AM »
In my case, on a very modern machine, I did this:

sudo isohybrid <path/to/your/iso>

this is what made me think we don't have isohybrid.
in any way, wouldn't it be worth mentioning on http://tinycorelinux.net/downloads.html ?

and @pdp8
of course tinycore is what inspired me to start using isolinux and syslinux more frequently again...
any time i can avoid grub i'm happy and nowadays i'm well aware of most possibilities.
tinycore has been extremely educative to me in this sense.

still covering all lowest common denominator hardware situations, and as many compatible generic boot possibilities are obviously useful in many ways.
personally i keep hard drives and flash drives with isos around, and some empty flashdrives so that i can easily dd an iso to it and boot without a keypress, instead of having to change boot configurations in grub, syslinux, etc. or going through some boot menu to select the iso i just downloaded...

sometimes for a single shot or bootstrapping thingy it's just the most convenient to take an iso and boot it from a cd or flash drive.

example negative scenario: you add an iso to your multi boot stick, but you don't know if it's gonna default auto boot into that or into another older kernel or distro, you boot, but you didn't look closely and you miss the opportunity to Cursor-Down and then you have to wait 1 minute for the acpi in order to hard reboot and try again ;)
« Last Edit: August 19, 2020, 06:36:51 AM by hiro »

Offline PDP-8

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Re: ISOHYBRID solves DD woes!
« Reply #9 on: August 19, 2020, 02:14:52 PM »
erm, many ways to do this, but I don't want to tell the project what to do..

Some ideas:
main repo could include additional isos in separate directories like

..iso/TinyCorePure64
..iso/isohybrid/TinyCorePure64

But where does it become ridiculous with versions ranging from using --uefi or -partok or any other number of variables...

But cool, now I know CorePlus is isohybrid and others aren't.  Simple to rectify on my end.
That's a UNIX book! - cool  -- Garth