Session 33 — 2026-03-29d — ebc-probe Crashes Kernel; sysfs Readout Safe

Session 33 — 2026-03-29d

FieldValue
Date2026-03-29
Phase03b — TWRP (ebc-probe testing)
Duration~30 min

ebc-probe — Abandoned

Cross-compiled ebc-probe.c with aarch64-linux-gnu-gcc -static. Two attempts, both caused kernel panic → 900E EDL dump mode:

  • Attempt 1: All phases (ioctl 0x7000–0x7024 with zeroed buffers) → kernel panic → 900E
  • Attempt 2: Phase 1 only (ioctl probe with zeroed buffers, no mmap) → kernel panic → 900E

Device recovered to TWRP automatically both times. The EBC driver’s ioctl handler does not tolerate probing with zeroed/dummy buffers when SurfaceFlinger/HWC is not running. ebc-probe cannot be used in TWRP. Running it requires a full Android boot.

sysfs Readout — Safe

Reading /sys/devices/sepdc/* is safe in TWRP (no crash):

AttributeValue
panel_initok
waveform_versiononyx waveform sg
wf_status99 (idle)
epdc_active_luts[0x0][0x0][0x0][0x1] — 1 active LUT
update_disable0 (updates enabled)
frame counter245:243

Decision

Skip ioctl probing entirely — go straight to kernel NOP patch. Apply patch-kernel-waveform-transform.py to extract kernel, NOP the BL 0x427a8c at 0x41d410, repack boot.img, flash via TWRP, test A2 visually.

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