More actions
| MacBook Pro A1990 Restarting repair | |
|---|---|
| Device | MacBook Pro A1990 |
| Affects part(s) | TouchBar, Main Logic Board |
| Needs equipment | Screwdrivers |
| Difficulty | ◉◉◉◌ Hard |
| Type | Parts Disassembly"Parts Disassembly" is not in the list (Soldering, Teardown, Part replacement, Cleaning, Software, BGA, General) of allowed values for the "Repair Guide type" property. |
Problem Description
MacBook Pro 15” A1990 randomly restarts shortly after boot. Before restarting, you may notice the trackpad freezing for a few seconds, and then macOS triggers a kernel panic.
A panic log shows BridgeOS panic, which drives the Touch Bar.
This issue is commonly caused by a faulty Touch Bar or BridgeOS communication failure, not by macOS, SSD, or user data.
Symptoms
- Mac boots to macOS, but freezes shortly after startup.
- Trackpad stops responding before reboot.
- Device restarts on a loop.
- Touch Bar not working (blank or unresponsive).
- No liquid damage or visible board damage.
- Apple Diagnostics and Disk Utility show no errors.
- Issue persists in Safe Mode and Recovery Mode.
Diagnostic Steps
- Check Panic Log
- Panic log will mention bridgeOS issues.
- This confirms Touch Bar communication error.
- Visual Inspection
- Inspect Touch Bar flex cable and connectors for corrosion or physical damage.
- Check for pin damage at Touch Bar connector on logic board.
- Test Without Touch Bar
- Disconnect the Touch Bar flex from the logic board.
- Boot macOS and observe behavior.
- If restart loop stops, Touch Bar is confirmed faulty.
Solutions
Option 1: Disconnect Touch Bar (Temporary Fix)
- Disconnect Touch Bar flex from logic board and run Mac without Touch Bar.
- If system boots and stays stable, you’ve isolated the issue.
- Note: Device will run without Touch Bar functionality.
Option 2: Replace Touch Bar Assembly
- Replace Touch Bar or entire Top Case with a known-good part.
- This resolves BridgeOS crash and restores full functionality.