Start with the complete wiring overview and bill of materials. Confirm that your telephone is suitable and identify its network-block terminals before modifying anything.

Wiring overview: https://evilroot.net/RotaryCell/wiring-overview.html

Bill of materials: https://evilroot.net/RotaryCell/materials.html

Order the Audio/Reset A4 and AG1171 carrier boards using the provided manufacturing files. Print the three interior carriers and the appropriate rear USB-C mount for your telephone.

PCB ordering: https://evilroot.net/RotaryCell/ordering.html

Printed parts: https://evilroot.net/RotaryCell/printed-parts.html

Remove the original battery holder, add the required signal and power connections, fit the board into its printed carrier, and inspect every connection before continuing.

Preparation overview: https://evilroot.net/RotaryCell/lilygo.html

Wiring connections: https://evilroot.net/RotaryCell/lilygo-connections.html

Inspection: https://evilroot.net/RotaryCell/lilygo-inspection.html

Populate the AG1171 carrier with the specified through-hole components and Silvertel module. Prepare the cables connecting the LilyGO, Audio/Reset board, carrier board, and telephone.

Board assembly: https://evilroot.net/RotaryCell/assembly.html

Cable preparation: https://evilroot.net/RotaryCell/harnesses.html

Attach tabs and insulated leads to the 21700 cell, verify polarity with a multimeter, and connect BAT and BATN exactly as documented. BATN must remain isolated from system ground because it is part of the LilyGO battery-protection circuit.

https://evilroot.net/RotaryCell/battery.html

Upload the current RotaryCell firmware through the LilyGO ESP-USB port using the documented ESP32-S3 settings. Install and activate a compatible physical voice SIM, then confirm cellular registration.

Firmware: https://evilroot.net/RotaryCell/firmware.html

SIM setup: https://evilroot.net/RotaryCell/sim.html

Mount the LilyGO, Audio/Reset board, AG1171 carrier, battery, antenna, and rear USB-C connector inside the telephone. Connect Ring and Tip to the appropriate terminals on your phone’s network block; terminal arrangements vary between telephone revisions.

Installation: https://evilroot.net/RotaryCell/mounting.html

Rear connector: https://evilroot.net/RotaryCell/connector.html

Begin with both audio trimmers near their midpoint, place test calls, and adjust the earpiece and microphone levels as needed. Confirm rotary dialing, incoming and outgoing audio, switchhook operation, mechanical ringing, charging, and battery operation before closing the case.

Audio adjustment: https://evilroot.net/RotaryCell/audio.html

Final checks: https://evilroot.net/RotaryCell/checks.html