• 1-Wire
  • Intermediate
  • 5 min
  • Serial CLI

Recipe · Intermediate · 1-Wire

How to copy an RW1990 iButton

Open the 1-Wire iButton shell to read a Dallas key ID and write it to a compatible RW1990 test key.

1-Wire iButton token.
A practical ESP32 Bit Pirate recipe based on documented firmware commands.
Step 1

Commands

Run this sequence from the CLI. Adjust pins, addresses or filenames to match your own setup.

Result

What it means

The shell keeps the device-specific sequence separate from manual bytecode and gives a safer path for repeated iButton tests.

Troubleshooting

  • Re-enter the selected mode setup if pins changed.
  • Confirm the target shares ground with the ESP32 Bit Pirate.
  • Start with short commands before using longer capture or bridge sessions.

Next steps

  • Read the copied key again to confirm the ROM ID.
  • Save notes about the reader wiring.
  • Use sniff to observe a reader talking to the key.

RW1990 copy FAQ

What kind of target is this workflow for?

Use it only with compatible rewritable RW1990-style lab keys that you own or are authorized to test. A normal DS1990A-style iButton is read-only and cannot be rewritten like a magic test key.

Why prefer USB Serial for iButton copy tests?

Programming timing is sensitive. A direct Serial CLI session avoids extra Web UI or Wi-Fi activity that can disturb timing during copy or write operations.

Why use a writable RW1990 for copy tests?

RW1990-style keys are lab targets intended for writable iButton experiments. They let you test copy behavior without modifying an original key or relying on a read-only device.

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