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Author Topic: ISO / UEFI issue finally found!  (Read 111 times)

Offline PDP-8

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ISO / UEFI issue finally found!
« on: July 25, 2020, 01:24:30 AM »
Found the problem with UEFI-only iso booting problem!

Armed with a pile of gear, finally something repeatable has been discovered.

tldr:  the TCPure64iso strictly follows the cd optical standard, whereas most other bootable distro's don't!  Perhaps a way that iso-hybrid is used as compared to the rest of the linux community which allows them to defeat optical-boot choices in uefi-only mode.

Discovery: Using the flexibility of the Intel NUC as the standard.

When placed into UEFI-ONLY mode, the standard is NOT to allow for "optical" boot, which the usb-stick masquerading as a cdrom is.

As such, even burned with the common user level "Etcher", predictably it will not boot.

When the NUC is manually adjusted to allow for "optical boot" - and STILL in uefi-only mode - the stick will boot without problem!

ALL OTHER 64-bit distros do NOT honor this switch in uefi-only bios.  They simply don't care if "optical boot" is enabled or not.  They boot anyway!

HOCKEY PUCK mini-pc:
The bios in this one has no user-controllable way to allow for "optical" booting.  Thus it will not boot TC using the usual dd/burners.

However, all other 64-bit distros that I tried with simple dd/burners, don't seem to care at all and boot anyway!

SO - this finally answers the question of why I use multibooters or other advanced USB stick burners to "fool" the UEFI-only bios if they have "optical" switched off, or simply do not have that option at all.

You'll note that I purposely left out Secure-Boot, as that is NOT the primary issue.
AND, neither is "legacy boot / csm", although they typically ALLOW for "optical booting" by default!

Is it any wonder why I let out a scream into a paper-bag?  <grin>  I'm just glad I finally have an answer.

Could it be something as simple as an additional flag needing to be applied to the iso-hybrid step so that it will not pay attention to the uefi-only "optical" choice and just cruise on in to booting?

Ok, that's off my bucket list!

That's a UNIX book! - cool  -- Garth

Offline aus9

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Re: ISO / UEFI issue finally found!
« Reply #1 on: July 25, 2020, 01:31:30 AM »
interesting post!

Have you tried to trick those pesky computers with plop?

Normally plop is made as a cd for older PCs that lack bios usb boot device support and you would go
plop cd....plop menu....usb stick

But you might be able to kind of reverse that so it might be
plop usb....plop menu....TC iso

Offline PDP-8

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Re: ISO / UEFI issue finally found!
« Reply #2 on: July 25, 2020, 02:08:48 AM »
Heh, it's in the dev's hands on how they want to handle it.

I'm good either way, since I can band-aid it by by allowing for "optical boot" in those machines that allow for making uefi exceptions, or use 3rd-party front-ends which do that for me.

What really threw me was that most other linux distro iso's simply boot in uefi-only mode regardless of how the "optical boot" switch is set in bios, whereas TC seems to care when in uefi-only.

And the fact that the makers of the modern mini-pc's may not have even been born when CD's were a "thing", may have thought that putting in that switch to allow for optical booting would be like having support for 9-track mag-tape streamers in the Linux kernel today. :)

Despite sounding like a smart-aleck, this was a total blast to finally figure out.  Only TC can push me like that.  Other non-core distro's - meh, just ignore and move on.
That's a UNIX book! - cool  -- Garth

Offline Leee

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Re: ISO / UEFI issue finally found!
« Reply #3 on: July 25, 2020, 09:44:03 AM »
Quote
And the fact that the makers of the modern mini-pc's may not have even been born when CD's were a "thing", may have thought that putting in that switch to allow for optical booting would be like having support for 9-track mag-tape streamers in the Linux kernel today. :)

Despite sounding like a smart-aleck, this was a total blast to finally figure out.  Only TC can push me like that.  Other non-core distro's - meh, just ignore and move on.

You don't sound smart-alecky to me.  This stuff is fascinating and I thank you for figuring it out and posting the result... and ISO booting isn't even something I care about- today, though that could change at a moment's notice if I ever get newer hardware.     :)

Any way to boot from paper tape?      ;)
coors
core

Offline PDP-8

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Re: ISO / UEFI issue finally found!
« Reply #4 on: July 25, 2020, 02:18:25 PM »
Yeah, it was just a matter of juggling too many variables and dead ends that finally came together with my pile of uefi hardware that acts differently from each other.  Once I settled on the Intel NUC being the final arbiter of what was going on, it became apparent.

In a nutshell:

1) The current iso as it is presents itself as an "optical" disk, whether you actually burn to optical media, or burn to a usb stick.

2) Legacy computers can boot to optical by default, unless steps are taken to block it.  The sledge-hammer approach recommended everywhere was to disable uefi and put your machine into legacy / csm.  So yeah, that works, (if your box can do that), but is like throwing the baby out with the bathwater.

3) UEFI-only boxes may or may not boot optical media.  The tendency is to NOT boot optical media, however manufacturers CAN override this as a default, and as such, some users may face no issues and think I'm going on a rant for no reason. :)

4) Ultra-modern things like uefi-only mini-pc's, or conventional laptops made within the last decade, tend not to have any options for enabling booting from optical media.  Kind of like asking a car-salesman where the cd/dvd player is on the dashboard, and finding out they haven't supplied that since 2011.

5) Secure-boot conspiracies.  Usually mixed in with any mention of UEFI.  Easily defeatable by the consumer.  AND, depending on where you get your machine, it might not even be enabled when you get it!  Secure-boot usually takes the booting discussion way off the rails.

6) Most modern distro's build their iso's so that they do not present themselves as optical media.  But the modern user doesn't know that the TC distro does, and may run into problems, and be guided down total dead ends and other conspiracy theories.

I'm just glad I figured it out so I can take the proper steps to handle it.

Re: tape booting?  Everyone knows that real computer operators toggle their bootloader in by themselves in octal with switches on the front panel.  Maybe that's the ultimate retro-solution!  :)


That's a UNIX book! - cool  -- Garth