Booting issue on Verdin AM62 S 512MB WB IT

Technical Support
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Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

Based on your description, this appears to be a complex boot issue with your Verdin AM62 SoM on the Mallow carrier board. Let me help you troubleshoot this systematically.

Analysis of Your Boot Sequence

Your issue progression suggests a few potential causes:

1. Initial “No working init found” Error

This typically indicates either:

  • Corrupted root filesystem on the SD card
  • Incorrect root filesystem parameters in U-Boot
  • eMMC interference with the boot process

2. Complete UART Silence After eMMC Operations

The fact that you lose all UART output (including ROM/SPL) after eMMC operations is concerning and points to potential hardware issues.

Troubleshooting Steps

Step 1: Verify U-Boot Environment Variables

When you can access U-Boot, check these critical variables(1):

> printenv boot_targets
> printenv root_devtype
> printenv root_devnum
> printenv fdtfile

Ensure boot_targets includes mmc1 for SD card boot and verify the root filesystem parameters are correct(1).

Step 2: Check Root Filesystem Parameters

The “No working init found” error often relates to incorrect bootargs. Verify your tdxargs variable(1):

> printenv tdxargs
> printenv bootargs

Step 3: Hardware Diagnostics

Given the complete UART silence after eMMC operations, this could indicate:

Power Supply Issues: Similar symptoms have been reported with poor quality power supplies(2). Even if your power supply works with other modules, this specific SoM might be more sensitive.

eMMC Hardware Failure: The eMMC might be corrupted or failing, causing boot conflicts.

PMIC Issues: Power management IC problems can cause complete boot failure without any UART output.

Step 4: Recovery Attempts

  1. Try a different power supply - This has resolved similar issues in the past(2)

  2. Use Toradex Easy Installer Recovery Mode:

    • Boot into recovery mode using the recovery button
    • Completely erase and reflash the eMMC with a known-good Toradex image
    • Test if the module boots normally with the reference image

  3. Test with minimal configuration:

    • Remove all unnecessary peripherals
    • Use only essential connections (power, UART, SD card)

Step 5: Verify SD Card and Image

  • Test your SD card on a PC to ensure it’s not corrupted
  • Try a different SD card with the same image
  • Verify your Yocto build by testing it on a working Verdin AM62 module first

Potential Root Causes

Based on the symptoms and similar cases:

  1. Hardware failure - Most likely given the complete UART silence
  2. Power supply quality issues(2) - Even with “good” supplies, some modules are more sensitive
  3. eMMC corruption - Could cause boot conflicts even when booting from SD
  4. PMIC configuration issues - Might be triggered by the eMMC operations

Recommendation

Since you have complete UART silence after the eMMC operations, this strongly suggests a hardware issue rather than a software configuration problem. I recommend:

  1. Testing with a different, high-quality power supply
  2. If the issue persists, this SoM may need hardware diagnosis or replacement
  3. Contact Toradex support for potential RMA if the module is under warranty

The fact that other identical modules work fine with the same setup indicates this is likely a hardware-specific issue with this particular SoM.

Best regards, Toradex AI Assistant.

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