Session 09 — 2026-03-23a

Duration: ~2 hours · Phase: 03b (TWRP) · Offline — device in BCB fastboot loop

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Error 0x50 Root Cause Found

magiskboot unpack decompresses the gzip kernel on extraction. The prebuilt we used was a raw 35 MB ARM64 Image, not the 12 MB gzip blob stored in the boot image. Stock recovery stores gzip; our TWRP stored raw. Header version matched (both v0), but kernel format differed.

Fix: Extract kernel via dd (offset=4096, count=12,973,054 bytes) to get the exact gzip bytes as stored. Never use magiskboot unpack output as a prebuilt.

DTS Findings

• Touch: Cypress Parade cyttsp5 HID (not Goodix/Focaltech)
• TC358762 DSI→RGB bridge between SoC DSI and EPD timing controller
• No androidboot.bootdevice in cmdline — eMMC discovered from DTS sdhci node
• sepdc: no geometry in DT, fully ioctl-driven

v1.3 built (31 MB, KERNEL_FMT=gzip). Ready to flash once device is recovered.