Add override and mfr_util configuration files

[ArunSundar-1805]

Problem

1) hciuart.service Failure

hciuart.service intermittently fails during system boot with the following error:

Can't open serial port: No such file or directory

This occurs because hciuart.service attempts to access /dev/ttyAMA0 before the UART device is fully initialized.

As a result:

• The service enters a failed state during boot.

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2) oem-first-boot.service Failure

oem-first-boot.service fails during boot with the following error:

[OEM-FIRST-BOOT] Error: 'mfr_util' not found in PATH

This occurs because the service depends on mfr_util, which is not available in the Raspberry Pi RDKE vendor image.

As a result:

• The service exits with failure.
• systemd reports a failed unit during boot.
• Boot logs contain unnecessary failure messages.

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Root Cause

hciuart.service

A boot-time race condition exists where:

• /dev/ttyAMA0 is created asynchronously during system initialization.
• hciuart.service may start before the device becomes available.

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oem-first-boot.service

A missing runtime dependency exists where:

• oem-first-boot.sh requires mfr_util.
• The binary is not present in the target image.
• The service executes unconditionally and therefore fails.

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Solution

hciuart.service

Added a systemd drop-in override:

systemd_units/hciuart.service.d/override.conf

The override:

• Adds ordering and dependency on dev-ttyAMA0.device.
• Performs a pre-start device availability check.
• Enables automatic restart on failure.

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oem-first-boot.service

Added a systemd drop-in configuration:

systemd_units/oem-first-boot.service.d/00-mfr-util.conf

The drop-in:

• Adds:

ConditionPathExists=/usr/bin/mfr_util

• Ensures the service only runs when mfr_util is available.
• Prevents unnecessary service failures when the dependency is absent.

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Implementation

Added the following files:

systemd_units/hciuart.service.d/override.conf
systemd_units/oem-first-boot.service.d/00-mfr-util.conf

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Result

hciuart.service

• Waits for /dev/ttyAMA0 availability before startup.
• Eliminates intermittent boot failures.

oem-first-boot.service

• Skips execution when mfr_util is unavailable.
• Prevents unnecessary boot-time service failures.
• Produces cleaner systemd boot status and logs.

[github-actions]

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[ArunSundar-1805]

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[Copilot]

Pull request overview

Adds systemd drop-in configuration intended to (1) prevent oem-first-boot.service from failing when mfr_util is absent, and (2) harden the Bluetooth UART bring-up service against boot-time /dev/ttyAMA0 availability races.

Changes:

• Add a drop-in for oem-first-boot.service to skip starting unless /usr/bin/mfr_util exists.
• Add a drop-in override intended for the UART/Bluetooth service to wait for /dev/ttyAMA0 and restart on failure.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
systemd_units/oem-first-boot.service.d/00-mfr-util.conf	Adds a systemd ConditionPathExists to skip the unit when mfr_util is not present.
systemd_units/hciurart.service.d/override.conf	Adds ordering on dev-ttyAMA0.device, a pre-start wait loop, and restart policy for the UART/Bluetooth unit (but currently has correctness issues noted in comments).

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