Boot messages

balanga · 2026-02-15T18:34:35+0000

Do the messages which are highlighted during the boot process get written anywhere?

I'm talking about messages such as start FB_INFO and the following block.

dmesg does not show such messages. Is there some way to get them recorded?

atax1a · 2026-02-15T18:39:52+0000

what block? have you tried looking at files in, say, /var/log? or are you just trying to provoke conversation to feed into your slop bot

Isoux · 2026-02-15T18:44:03+0000

No, those messages are not written to dmesg.

The messages you see during the very early boot phase (loader, BTX, and early kernel initialization) are printed directly to the console before the kernel message buffer is initialized. Because of that, dmesg does not contain them.

The boot sequence roughly goes like this:

MBR / boot0
loader (BTX)
kernel entry
early kernel initialization
console attach
message buffer becomes active (used by dmesg)

Anything printed before the message buffer is set up will not be recorded.

If you need to capture the complete boot output, the reliable method is to use a serial console and log the output (or serial capture in a virtual machine).

Enabling verbose boot (boot_verbose="YES") may show more kernel messages, but it still does not cause loader-phase messages to appear in dmesg.

atax1a · 2026-02-15T18:53:17+0000

Isoux said:
If you need to capture the complete boot output, the reliable method is to use a serial console and log the output (or serial capture in a virtual machine).

yes, this.

balanga · 2026-02-15T19:28:10+0000

atax1a said:
what block? have you tried looking at files in, say, /var/log? or are you just trying to provoke conversation to feed into your slop bot

So you think those messages get recorded in /var/log ??

That was the obvious place to look.

atax1a · 2026-02-15T19:35:41+0000

generally speaking when you're asking for help it's a good idea to explain what you already tried. also to explain which messages you're looking for — a photo of the screen would have clarified immediately, for example.

jwillia3 · 2026-02-15T19:44:14+0000

dmesg -a shows syslog and console output.

drhowarddrfine · 2026-02-15T21:25:08+0000

atax1a said:
a photo of the screen would have clarified

Don't do photos. Copy/paste the actual text.

MG · 2026-02-15T21:31:56+0000

jwillia3 said:
dmesg -a shows syslog and console output.

I remember to scroll back to the bootloader output but I can't get there anymore. It seems to be removed. Maybe the kms graphics can't remember it after changing resoluton.

atax1a · 2026-02-15T21:35:18+0000

drhowarddrfine said:
Don't do photos. Copy/paste the actual text.

it's. a little difficult to copy/paste the actual text of a message, before there's a kernel buffer to capture it.

atax1a · 2026-02-15T21:36:53+0000

MG said:
I remember to scroll back to the bootloader output but I can't get there anymore. It seems to be removed. Maybe the kms graphics can't remember it after changing resoluton.

was that on a BIOS machine? it's conceivable that a BIOS boot could leave the vga scrollback intact, but the UEFI handoff is going to tear down the boot services and lose the text.

MG · 2026-02-15T21:50:41+0000

atax1a said:
was that on a BIOS machine? it's conceivable that a BIOS boot could leave the vga scrollback intact, but the UEFI handoff is going to tear down the boot services and lose the text.

Very good chance. The legacy kernel screen was still the 80x25 hardware console.
Kind of a loss. It's good to be able to look back until power-on.