Create isoboot which will allow an ISO image to be booted from a USB stick
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Authored by imp on Mar 22 2018, 5:05 PM.

Details

Reviewers

kevans
mav
kmoore
jhb
benno
manu

Summary

This creates a version of i386's boot2.c that, instead of reading from a UFS partition, will read from an ISO filesystem.

Test Plan

A FreeBSD bootonly ISO image built with this can be found here:

https://people.freebsd.org/~benno/hybrid-bootonly.iso.xz

This has been tested successfully under qemu and VMware in the following configurations:

Legacy BIOS as CD
Legacy BIOS as HDD
UEFI as CD
UEFI as HDD

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Unit

Tests Skipped

Build Status

Buildable 15723

Event Timeline

benno created this revision.Mar 22 2018, 5:05 PM

Harbormaster completed remote builds in B15723: Diff 40603.Mar 22 2018, 5:05 PM

franco_opnsense.org added a subscriber: franco_opnsense.org.Mar 22 2018, 8:32 PM

vidwer_fbsdbugs_gmail.com added a subscriber: vidwer_fbsdbugs_gmail.com.Mar 24 2018, 4:23 PM

Both hybrid-bootonly-20180323-00.iso and hybrid-bootonly.iso fail to boot to userland on coreboot 4.14 + SeaBIOS 1.14, and about 50 seconds into booting panic at stand/libsa/zalloc_malloc.c:131
Crash details shown on screen are:
"panic: free: guard1 fail @ 0x5ceb7fe0 from unknown:0
--> Press a key on the console to reboot <--"

Loader reports 'BIOS 639kB/1570068kB available memory'

These .iso files were written to USB media using dd.

Updated on 2021-07-19 to mention firmware release information, crash report text and line number, and update memory report details.
If desired, I can share photos of what's on the screen.

This should be in sys/i386/isoboot, not co-located with sys/i386/boot2. While it mildly benefits from having boot1 sharing, it can get that via a reach-over as well.

And do we need the same sort of structure with a boot1 that reads the rest of the boot block? Doesn't sharing limit this to 7.5k as well, when the limit is closer to 32k?

stand/i386/boot2/Makefile
5	I'd make this a separate directory, like we've done for gpt boot. There appears to be no benefit from sharing the same directory.

grahamperrin added a subscriber: grahamperrin.Jul 18 2021, 2:22 AM

Herald added a subscriber: dab. · View Herald TranscriptJul 18 2021, 2:22 AM

imp commandeered this revision.Jul 18 2021, 2:45 AM

imp edited reviewers, added: benno; removed: imp.

This has my attention, so I tried booting a hybrid Debian ISO [1]. Booting this ISO file using the same firmware build as mentioned earlier successfully loaded the kernel (and beyond).

Thomas Schmitt suggested to run xorriso [2].

Here are some of my observations after running 'xorriso -indev hybrid-bootonly.iso -report_el_torito plain -report_system_area plain'.
For hybrid-bootonly.iso, hybrid-bootonly-20180323-00.iso:
System area summary: MBR cyl-align-off

For debian-live-10.10.0-amd64-standard.iso:
System area summary: MBR isohybrid cyl-align-on GPT

[1] https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/debian-live-10.10.0-amd64-standard.iso
[2] https://lists.freebsd.org/pipermail/freebsd-current/2018-March/068928.html

That said, on 14-CURRENT dd'ing bootonly.iso/disc1.iso to USB media the boot experience is the same as booting memstick.img.

This appears to have been taken up by Benno before he disappeared and much of this is in the tree. Closing

Herald added a reviewer: manu. · View Herald TranscriptMar 15 2023, 4:55 PM