Skip to main content
When using USB-PD power supplies with IronOS devices, you may occasionally encounter boot issues, reboots, or power negotiation failures. This guide helps diagnose and resolve USB-PD compatibility problems.

​
Common Issues

USB-PD problems typically manifest in three ways:
  1. Device doesn’t power up at all
  2. Device powers up but reboots continuously
  3. Device reboots when heating starts

​
Root Causes

  • IronOS PD stack bugs or incompatibilities (rare)
  • Power adapter issues or quirks
  • “Smart” adapters with compatibility problems
  • Insufficient power delivery capacity
  • Cable limitations
Unique Load Pattern: Soldering irons rapidly switch from 0 to full power, unlike laptops/phones that ramp gradually. This can trip protection circuits on some power supplies.
Best Choice: Normal, boring 60-100W single-port PD supply.

​
What to Avoid

Multi-port marketing tricks: Watch for 65W adapters with multiple ports (e.g., 45W + 20W) that cannot deliver 65W to a single port.
  • Multi-port adapters at full capacity
  • “Smart” chargers implementing every protocol
  • Budget adapters with shortcuts in PD implementation
  • Adapters with aggressive protection circuits

​
Smarter Chargers

Chargers implementing many protocols (QC, PD, PPS, AFC, etc.) may have quirks:
  • Slight shortcuts in PD implementation
  • Protocol switching issues
  • Hard-to-debug compatibility problems

​
Device Doesn’t Power Up

This is the most frustrating issue to diagnose.

​
Step 1: Rule Out Other Issues

1

Test with USB-A to USB-C

Connect using a USB-A to USB-C cable (5V power) to rule out:
  • Bad firmware flash
  • Non-functioning display
  • Hardware failure
2

Test with DC power

If available, test with a DC barrel power supply to verify basic functionality.

​
No Power on Any Supply

If the device won’t power up on any supply type:
  1. Check bootloader access: Hold down the button while connecting to a computer
  2. Verify detection: Check if the device appears in device manager / system
If the device shows up to a computer but doesn’t operate normally:
  • Bad flash/firmware (most likely)
  • Non-functioning display (device may be working but not showing output)
Try pressing the front button to test heating function.

​
Powers Up on Other Supplies

If the device works with USB-A or DC but not USB-PD:
1

Test different PD supply

Try another USB-PD adapter to isolate adapter-specific issues.
2

Check cable

Use a different USB-C cable (preferably e-marked for high power).
3

Inspect connector

Look for debris or damage in the USB-C port.
Hardware Damage Possibility: If the device doesn’t power on with any PD supply:
  • Damaged PD PHY chip
  • USB connector CC pin damage
USB-PD uses CC pins not utilized by USB-A adapters, so USB-A may work while PD fails.

​
Device Reboots Continuously

​
Reboot During Heat-Up

If reboot occurs when the unit starts heating:
Power Supply Insufficient: The adapter cannot supply the requested power.
Solutions:
  • Use higher wattage power supply (60W minimum, 100W recommended)
  • Verify cable rating (non e-marked cables limited to 3A)
  • Check adapter specifications match printed ratings
  • Try single-port adapter instead of multi-port

​
Reboot During Idle

If the device reboots frequently without button presses: Cause: PD negotiation failure
The Best Debugging Tool: Capture USB-PD traffic. Without a traffic capture, all debugging is guessing.

​
Capturing PD Traffic

To truly understand negotiation failures, you need to capture the PD communication.

​
Method 1: Logic Analyzer

  • Connect to CC pins on USB-C connector
  • Important: PD signaling is less than 3.3V
  • Use logic analyzer capable of less than 3.3V levels or add buffering
  • Capture during connection and negotiation phase

​
Method 2: USB Power Meter

Many high-end USB power meters can capture PD packets:
  • On-screen display (minimum)
  • File export capability (ideal)
Recommended meters with PD capture:
  • AVHzY CT-3
  • ChargerLAB POWER-Z
  • FNB58
Without a traffic capture, all debugging is guessing. Investment in a PD-capable meter pays dividends for any USB-PD debugging.

​
Firmware PD Mode Settings

Firmware 2.23+: Advanced settings include PD mode toggle to adjust negotiation behavior.

​
PD Mode Options

The firmware can enable/disable:
  • PPS (Programmable Power Supply): Dynamic voltage negotiation
  • EPR (Extended Power Range): Voltages above 20V (PD3.1)
PPS is known to be incorrectly implemented on some supplies. Disabling PPS and EPR can improve compatibility with problematic adapters.

​
Accessing PD Mode Settings

  1. Navigate to Settings → Advanced Settings
  2. Find PD Negotiation option
  3. Toggle between modes:
    • PD + PPS + EPR (full featured)
    • PD + PPS (no EPR)
    • PD Only (maximum compatibility)

​
PD Debug Menu

Pinecil Devices: Boot while holding the front button to enter PD debug menu.
The debug menu displays:
  • Advertised voltage levels
  • Available power profiles
  • Current negotiation state
  • EPR capability status

​
Viewing Debug Menu

1

Remove tip

Remove the tip from the iron. Most devices won’t negotiate PD without a tip installed (waiting to detect tip type). This prevents failing negotiations.
2

Hold button and connect

Hold front button while connecting to USB-PD supply.
3

Review advertised profiles

Compare displayed voltages/power with adapter specifications printed on the device.

​
What to Check

  • Voltage profiles: Match adapter specifications
  • Current limits: Verify cable rating (3A for non e-marked)
  • EPR availability: Requires EPR-rated cable
  • Profile selection: Confirm highest appropriate profile is chosen

​
Cable Requirements

​
Standard USB-C Cables

Non e-marked cables are limited to 3A (60W at 20V).

​
E-Marked Cables

Required for:
  • Power delivery above 60W (3A)
  • 5A operation (100W at 20V)
  • EPR modes (28V, 36V, 48V)
E-marked cables contain a chip that identifies their capabilities.

​
Cable Testing

If experiencing issues:
  1. Test with certified e-marked cable
  2. Use short cable (less than 1m) to reduce resistance
  3. Verify cable temperature during use (hot cable = excessive resistance)

​
Systematic Troubleshooting

Before filing a support request:
1

Test multiple adapters

Try 2-3 different USB-PD adapters from different manufacturers.
2

Test multiple cables

Use different USB-C cables, including at least one e-marked cable.
3

Try PD mode settings

Disable PPS and EPR to test compatibility mode.
4

Capture PD traffic (if possible)

Use logic analyzer or PD-capable meter to record negotiation.
5

Check PD debug menu

Verify advertised profiles match adapter specifications.

​
Filing Support Requests

When reporting PD issues, include:
  1. Device model and firmware version
  2. Power adapter: Make, model, specifications
  3. Cable: Type, rating, e-marked status
  4. Behavior: Specific symptoms and when they occur
  5. Testing results: What works, what doesn’t
  6. PD traffic capture: If available (exponentially helpful)
  7. PD debug menu: Screenshots or photos
  8. Settings: Current PD mode configuration
A PD traffic capture makes the problem exponentially easier to diagnose and fix. It’s the difference between guessing and knowing.

​
Resources

Build docs developers (and LLMs) love

Get started for freeTalk to us