# Core 2026.4.2 crashes with Signal 11 during onboarding — Pi 4B Rev 1.5, HAOS 16.3

Installation
1

Core 2026.4.2 crashes with Signal 11 during onboarding — Pi 4B Rev 1.5, HAOS 16.3

Hardware:

  • Raspberry Pi 4B Rev 1.5, 4GB RAM
  • SanDisk Endurance 64GB SD card
  • Official Raspberry Pi power supply
  • No USB devices connected

Software:

  • HAOS 16.3
  • Core 2026.4.2 (downloaded automatically on first boot)

What happens

After a fresh flash of HAOS 16.3 and os datadisk wipe:

  1. Core 2026.4.2 downloads successfully (~20 minutes)
  2. Browser shows “Preparing Home Assistant”
  3. Onboarding page appears
  4. After ~30 seconds: Core crashes with Signal 11

This happens on every attempt. No add-ons, no integrations, no database — completely fresh install.

Supervisor log (key lines)

2026-04-17 11:09:19 INFO Starting Home Assistant
2026-04-17 11:09:50 ERROR [supervisor.homeassistant.api] Can't update Home Assistant access token!
2026-04-17 11:09:55 INFO Updated Home Assistant API token
2026-04-17 11:10:03 ERROR Home Assistant Core state changed to APIState(core_state='NOT_RUNNING')
2026-04-17 11:10:03 ERROR Home Assistant has crashed!
2026-04-17 11:10:03 ERROR Can't start Home Assistant!

Core log (key lines)

[homeassistant.components.http.ban] Login attempt
[09:09:57] INFO: Home Assistant Core finish process exit code 256
[09:09:57] INFO: Home Assistant Core finish process received signal 11

Important context

  • Core 2026.4.2 ran successfully ONCE yesterday (onboarding completed, dashboard visible)
  • After moving the Pi and restarting: Signal 11 crash on every subsequent attempt
  • core update --version 2026.3.4 has never worked — always blocked by “another job is running” or “Unknown Flag”
  • Rolling back to 2026.3.4 is the documented fix for Pi 4 instability with 2026.4.x — but we cannot execute the rollback because Core crashes before any CLI command can be run

Question

Why does Core 2026.4.2 crash with Signal 11 on a fresh install with no configuration? Is there a way to force Core 2026.3.4 to be downloaded instead of 2026.4.2 on first boot?

2

The current version of HAOS is 17.2, AFAIK. Is there a reason why you’re installing 16.3???

3

That was an attempt to resolve but the problem remains in every version.

4

Have you tried another one? How to Troubleshoot Raspberry Pi Crashing

5

Thanks for your advice. I did that now but exactly the same problem. Crash during onboarding. (Tbh. I also find no plausible reason why this is caused by a SDcard problem but is was worth testing)

6

Where are you getting your source files from? Are you selecting the correct ones?
What instructions are you following?
Are you installing anything else prior to doing updates?
Have you restored from a backup prior to the error being encountered?
Is your Pi hardware faulty? Signal 11 is usually memory related, or a low power supply voltage issue? Try installing another Raspberry Pi OS (that is not HomeAssistant related) and verify that can run without errors to assure yourself it is not faulty.
Have you waited till the update process actually finished, and not started remedial activity prematurely while it was still finalising any updates? This can be an issue for newcomers, expecting a core OS Update to take minutes that can actually take many hours. Leave it overnight and check in the morning resolves most update issues.

7

Where are you getting your source files from? Are you selecting the correct ones? HAOS 16.3 image from GitHub releases: haos_rpi4-64-16.3.img.xz — correct image for Pi 4B 64-bit.

What instructions are you following? The official Home Assistant installation guide from home-assistant.io

Are you installing anything else prior to doing updates? No. Completely fresh install, no add-ons, no integrations, nothing added.

Have you restored from a backup prior to the error being encountered? No. No backup exists — onboarding was only completed once successfully.

Is your Pi hardware faulty? Signal 11 is usually memory related, or a low power supply voltage issue? Two different SD cards tested — same result. Official Raspberry Pi power supply used. The Pi runs fine otherwise — network works, CLI responds, Supervisor runs without issues. Only Core crashes.

Have you waited till the update process actually finished? Yes — the full 20-minute download completes successfully. Core starts, onboarding page appears in browser, then Signal 11 crash occurs approximately 30 seconds into the onboarding process. This is not a premature intervention — Core crashes on its own.

Key observation: Core 2026.4.2 completed onboarding successfully exactly once. Every subsequent start results in Signal 11 crash. Nothing changed between the successful run and all failed runs except a reboot.

8

Thanks for the feedback. Lots of possible issues crossed off the list.

9

Are you using this method of installation, using the imager software to get your files onto the SD Card?

10

Yes, I followed the official installation guide at Raspberry Pi - Home Assistant

The image was flashed using both Raspberry Pi Imager and dd via Mac terminal — same result with both methods.

11

In step 3 and 4, using the imager, which one did you select?

12

I selected “Home Assistant OS 17.2 (RPi 4/400)” in Raspberry Pi Imager v2.0.7.

Note: I also tried HAOS 16.3 previously, flashed manually via dd on Mac terminal using the image downloaded from GitHub. Same Signal 11 crash with both versions.

13

As the issue doesn’t seem to be reported widespread on these forums, it would point to something local and specific to you.

For problem isolation, try installing the standard Raspberry Pi OS from the imager, bring it up and see if it runs reliably for a while. If that also crashes, there is high likelihood it is your hardware that is faulty, and you can then try and narrow down the underlying cause with more specific diagnostics. Memory tests, drive tests, etc.
The bootup welcome screen may provide clues. Any chance of a clear readable screen shot?

14

Thank you. I understand the logic.

One question: without any load on the system, will Raspberry Pi OS really reveal a hardware fault? Home Assistant Core seems to be what triggers the crash — would a basic OS test without similar load be conclusive?

15

I have heard of rumors of an issue with RasPi’s that are not on the latest revision of internal EEprom firmware having some kind of issue.
Perhaps load the pi with a regular image and update the eeproms, then see if it solves.
Also in response SD cards can fail in the most unusual ways and cause pretty random failures. Even brand new ones sometimes.

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