BMW ICOM A2 Repair and Recovery — Step-by-Step Guide

🔧 Common Issues:

1. All LEDs are red or flash once

   • ATmega16 does not start.

   • Causes:

     • Dead or badly soldered ATmega16.

     • Missing clock signal.

     • Missing voltages (1.6V / 2.5V / 3.3V).

     • Faulty EEPROM (24C02).

2. ICOM not seen on LAN

   • LAN PHY chip Micrel KSZ8721BL failure.

   • Solution:

     • Check traces between LAN port, transformer, and Micrel.

     • Replace Micrel chip.

3. ICOM blinks green but doesn’t work

   • Spansion NOR Flash (S29GL064) is corrupted.

   • Needs reprogramming or replacement.

4. Fan Error / WLAN Fail

   • Device enters emergency mode.

   • Solution:

     • Connect 3-wire fan with speed sensor.

     • Error clears at startup.

     • To prevent it:

       • Change serial in EEPROM to 180120X.

       • Flash A2 firmware, not A1.

5. K-Line not working

   • Causes:

     • Wrong resistor (e.g., 3.9k instead of 39k).

     • Damaged inverters or VP234 transceiver.

     • Poor soldering or dead diodes.

🔄 USB Recovery Procedure:

1. Copy ICOM_Restore.bin to FAT32-formatted USB stick.

2. Insert USB into ICOM.

3. Press the button 3 times to enter recovery.

4. If nothing happens:

   • No USB 5V.

   • Faulty USB controller TUSB6250 (U1562).

   • Missing pull-up resistor (~100kΩ).

   • Empty or corrupted 24C02.

📦 Flashing Components:

• S29GL064 (Spansion NOR) — must be pre-programmed.

• K9F2G08 (Samsung NAND) — erase or replace.

• 24C02 EEPROM — change serial to 180120X for A2.

• VP234, MICREL, TUSB6250 — replace as needed.

🧪 Power Supply Checkpoints:

• USB: +5V, internal 3.3V / 2.5V / 1.6V

• Clock signal at ATmega16

• PCI initialization between CPU and USB controller

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