PAX A920 Bell MTS Android System Recovery Diagnostic -... | terminalfaults.org

Technical Background:

The Android System Recovery mode is a failsafe partition designed for system updates and data wipes. Unexpected voltage fluctuations, corrupted bootloader, or file system errors can trigger this mode. The A920's power management IC (PMIC) regulates voltage to critical components. Inconsistent power can corrupt data during write operations to flash memory (eMMC), leading to boot failures. Baud rate mismatch during firmware updates can also lead to corruption.

Symptoms:

The PAX A920 Bell MTS terminal is booting directly into Android System Recovery mode instead of the standard operating system.

Possible Causes:

Voltage spike from the Bell MTS power grid during the outage.
Corrupted Android operating system files or bootloader due to incomplete or failed update.
eMMC flash memory corruption due to power instability.
ESD (Electrostatic Discharge) damage to the device's internal components, especially in dry environments.
Baud rate mismatch during a prior firmware update (if applicable).
Cable strain or damage to the power adapter, resulting in unstable power delivery.

Solution:

1

Perform a hard reset: Press and hold the power button for 15 seconds to force a shutdown. Then, attempt to power the device on normally.
2

Check power adapter: Ensure the power adapter is securely connected to both the terminal and the power outlet. Inspect the cable for any signs of damage.
3

Try a different power outlet: Plug the terminal into a different power outlet to rule out issues with the original outlet.
4

Clear cache partition (via recovery mode): Using the volume and power buttons, navigate to the 'wipe cache partition' option in Android System Recovery and select it. This will not erase user data.
5

Factory data reset (via recovery mode): As a last resort, perform a factory data reset from the Android System Recovery menu. WARNING: This will erase all data on the device. Navigate to 'wipe data/factory reset' and select it. This will return the device to its original factory settings.
6

Re-apply Firmware (licensed technician only): Contact PAX support or Bell MTS for instructions on re-flashing the device's firmware. This typically requires specific tools and credentials.
7

Contact Support: If the issue persists after attempting these steps, contact PAX support or Bell MTS technical support for further assistance.

Safety Warning:

This device is a PCI-PTS certified payment terminal. Do NOT attempt to open the casing or tamper with the internal components. Doing so will trigger the anti-tamper mechanisms and permanently disable the device. Safe Handling: Disconnect the power adapter from the power outlet before performing any cleaning or inspection. Ensure your hands are dry. No LOTO required in a retail checkout environment.

Prevention:

Use a surge protector: Connect the terminal to a surge protector to protect it from voltage spikes.,Cable Management: Ensure the power cable is not strained or bent excessively. Use cable ties to manage the cable and prevent damage.,Regular Cleaning: Clean the touchscreen with a soft, dry cloth to remove dust and debris. Avoid using harsh chemicals or abrasive cleaners.,ESD Prevention: Use anti-static mats, especially during winter months, to minimize the risk of ESD damage. Ground yourself before touching the terminal.,Firmware Updates: Ensure all firmware updates are installed correctly. If an update fails, contact PAX support for assistance.,Proper Shutdown: Always shut down the terminal properly through the Android interface, instead of abruptly disconnecting power.

Expert Tip:

In Android System Recovery, the volume buttons are typically used for navigation, and the power button is used to select an option. If the touchscreen is unresponsive, try navigating using the physical buttons. If the terminal still boots to recovery, use `adb logcat` to see if there is a repeating error. This can identify a corrupted file. The A920 can sometimes be forced out of recovery using a specific key combination (Power + Vol Up + Vol Down) but this is model specific and may erase device encryption keys (AVOID unless instructed by the manufacturer).

Frequently Asked Questions

•What are the risks of performing a factory reset?

A factory reset will erase all data on the device, including installed applications, user settings, and transaction history. Ensure a backup is performed prior, if possible. However, given the state of recovery, a backup may not be possible.

•How can I prevent ESD damage to the terminal?

Use anti-static mats, especially during winter months when static electricity is more prevalent. Ground yourself by touching a grounded metal object before touching the terminal. Avoid wearing clothing that generates static electricity, such as wool or fleece.

•What should I do if the terminal is still stuck in Android System Recovery after attempting the solutions provided?

Contact PAX support or Bell MTS technical support for further assistance. They may have specific tools or procedures for re-flashing the device's firmware or diagnosing more complex hardware issues. Be prepared to provide the device's serial number and a detailed description of the problem.

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What are the risks of performing a factory reset?

•How can I prevent ESD damage to the terminal?

•What should I do if the terminal is still stuck in Android System Recovery after attempting the solutions provided?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: