PAX A920: Troubleshooting Unintended Android System... | terminalfaults.org

Technical Background:

The Android System Recovery menu is a failsafe partition accessed via specific key combinations during boot. The bootloader is likely detecting a condition that triggers this recovery mode. Intermittent voltage drops, corrupted boot flags, or persistent key presses can initiate this.

Symptoms:

The PAX A920 terminal consistently boots into the Android System Recovery menu instead of the standard operating system.

Possible Causes:

1. Accidental or stuck key presses during startup (e.g., Volume or Power buttons).
2. Corrupted boot partition or system files due to software update failure or data corruption.
3. Intermittent power fluctuations or voltage dips during the boot sequence.
4. ESD (Electrostatic Discharge) events causing temporary microcontroller glitches.
5. Firmware corruption.
6. Hardware malfunction of the power button or volume buttons.

Solution:

1

Safe Handling: Disconnect the power adapter from the PAX A920.
2

Inspect all buttons for physical obstructions or damage that might cause them to be stuck in a pressed position.
3

Reconnect the power adapter and attempt a normal boot. Observe if the issue persists.
4

If the device enters recovery mode, use the volume buttons to navigate to 'Reboot system now' and press the power button to select. Test to see if it boots normally.
5

If the problem continues, perform a factory reset from the Android System Recovery menu (Warning: This will erase all data on the device). Use volume keys to navigate and power button to select. (If this is allowed by company policy)
6

Ensure the power adapter being used is the original PAX A920 adapter or a certified replacement that provides the correct voltage and amperage.
7

Contact PAX support or an authorized service provider if the issue remains unresolved.

Safety Warning:

Risk of electrical shock exists. Always perform Safe Handling (unplugging the power adapter) before inspecting the device. Do not attempt to open the device casing, as this voids the warranty and may damage sensitive components. Increased risk of ESD in dry conditions. Avoid operating near liquids.

Prevention:

1. Regularly clean the device, paying attention to the buttons, to prevent debris buildup.,2. Ensure the power cable is properly connected and free from strain. Avoid placing the device where the cable may be easily damaged or disconnected.,3. Implement ESD prevention measures, especially in dry environments (e.g., anti-static mats).,4. Avoid abrupt power loss. Always power down the device properly.,5. Regularly check for and install any available software updates from PAX.

Expert Tip:

Try booting the device with no SIM card or SD card inserted to eliminate potential conflicts during the boot process. If recovery mode is password protected, document/backup the password. If volume buttons are suspected, a toothpick can sometimes gently release a stuck button.

Frequently Asked Questions

•What is the default password for the recovery menu?

There is no default password. A password may have been set by the service provider.

•Can I update the Android OS version in recovery mode?

Updating is possible via ADB sideload, but requires specific firmware images and technical knowledge. Contact your vendor.

•What is the warranty policy if I factory reset the terminal?

Factory resetting does not affect the warranty; however, tampering with the device's internals will void it.

PAX A920: Troubleshooting Unintended Android System Recovery

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the default password for the recovery menu?

•Can I update the Android OS version in recovery mode?

•What is the warranty policy if I factory reset the terminal?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: