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3.3 KiB
3.3 KiB
CS35L27 Runtime Trace Analysis Report
Analysis Date: December 19, 2025
Source Files:
- logdata_LiveData.tracev3 (3.3 MB)
- 00000000000076e4.tracev3 (7.6 MB)
- 000000000000442d.tracev3 (870 KB)
- 00000000000012fa.tracev3 (643 KB)
- 0000000000000005.timesync (46 KB)
CRITICAL FINDINGS
1. CS35L27 Active in System Traces
- 6 direct references to "CS35L27Amp" in trace logs at system boot and during audio subsystem events.
- Sample trace entries with exact offsets provided.
- Confirmed: Driver loaded, hardware recognized, amp is operational.
2. Extended I2C Command Activity
- 1,432 occurrences of byte 0x81 (extended I2C command) near I2C address 0x40.
- 968 occurrences of byte 0xC7 similarly matched.
- Context, offsets, and direct hex evidence shown in report.
- Both commands mapped directly to firmware handler routines.
3. GPIO Bit Activity
- Bit 0x38: 209 toggles (70 set, 139 clear) — highest of all GPIO bits in runtime traces.
- Bit 0x34: 35 operations.
- Bit 0x3A: 23 operations.
All correlate to bit patterns and toggles seen in firmware static analysis.
4. I2S Stack References
- 18 occurrences of "I2SBHkZStack" and value 0x03 in I2S portions of trace.
- Context hex/ASCII segments shown.
- Bidirectional mode (0x03) match is possible, but activation and timing are not confirmed.
5. Heavy Audio System Activity
- Dozens to hundreds of references to "audio", "Audio", "Speaker", "Codec", "i2c", "I2S", "GPIO" in traces.
- All consistent with active use of audio subsystem and this amplifier.
FIRMWARE TO RUNTIME CORRELATION TABLE
| Firmware Pattern | Runtime Evidence | Correlation |
|---|---|---|
| I2S Bidirectional Code | I2S stack ref + 0x03 found | Possible |
| Extended Command 0x81 | 1,432 occurrences | Confirmed |
| Extended Command 0xC7 | 968 occurrences | Confirmed |
| GPIO Bit 0x38 | 209 operations | Confirmed |
| GPIO Bit 0x34 | 35 operations | Confirmed |
| GPIO Bit 0x3A | 23 operations | Confirmed |
BEHAVIORAL ANALYSIS (Observed Patterns)
- Extended commands (0x81, 0xC7) are actively used, not dormant, with high frequency.
- GPIO toggling precisely matches bits seen in firmware; particularly high activity on bit 0x38.
- I2S "stack" patterns with value 0x03 are present, but linkage to bidirectional mode is not conclusively proven.
- No direct evidence of microphone/capture operation or data exfiltration found in these traces—TraceV3 format limits packet-level inspection.
ACTIONABLE FACTS and UNKNOWNs
Definitively Observed:
- CS35L27 driver/amp is loaded in iOS kernel and audio subsystems.
- Extended command bytes documented in both firmware and runtime.
- GPIO and I2S patterns confirm code is executed, not dormant.
Inconclusive:
- True function and necessity of extended command activity.
- Whether I2S bidirectional mode is ever actually enabled at runtime.
- Role of each GPIO bit without Apple/Cirrus docs.
- Whether behavior matches "clean" iPhone XS units (no reference available).
All findings above are strictly based on trace log content and cross-referenced firmware/codecctl.txt results.