So far couple of issues were identified:
- ODROID-N2: Fails to boot with certain eMMC modules. Root cause identified, reverted in the stable channel. Should eventually boot after couple of power cycles, running
ha os update --version 14.2afterwards should fix it as suggested here: Update to HAOS 15.0 fails on Home Assistant Blue / Hardkernel ODROID-N2/N2+ · Issue #3938 · home-assistant/operating-system · GitHub - HP t620: More details needed, if you can reproduce the issue, see: HP T620 stuck after HAOS15 update · Issue #3944 · home-assistant/operating-system · GitHub
- Raspberry Pi 5: Intermittent update issues are present already since previous versions. One issue was fixed in OS 15.0 (meaning the update to this version is needed at first to fix it). With some patience and direct access to the device the update should be achievable, see Raspberry Pi 5 stuck after an OS update · Issue #3943 · home-assistant/operating-system · GitHub
If you are affected by any of these issues and the suggested solutions do not work for you, please follow the instructions on how to gather details in the individual issues. In case your problem is different from the above (different hardware, OS fails in a different way), open another issue with details about your setup and how the issue can be reproduced. If you can’t do that, just subscribe to any of the issues to reduce the clutter, spamming random issues with unrelated problems makes it hard to keep the track for maintainers.