Some months ago my Chromecast with Google TV 4K died mid-OTA update. Rebooted and never came back. Now it boots to the Google TV logo and sits there forever. Tried the obvious stuff like hard resets, different cables, button combinations. Nothing. Put it in a drawer.

Recently I got annoyed enough to actually dig in. I'm not a developer, so I had no idea what I was doing but I was too stubborn to stop. What followed was several days across four computers and three operating systems, Windows ARM, Windows x64, and MacOS before finally remembering I had an old Linux laptop gathering dust somewhere. Things started making sense on Linux. And then got worse.

What I tried:

ADB/Fastboot: Device shows up as "GX-CHIP" meaning the hardware is alive, but standard Android tools can't communicate with it.

Amlogic USB Burning Tool: Actually detects it and shows "Connect success." But no compatible firmware image exists for this model in the format the tool needs.
Also fought driver issues on both the ARM laptop and the x64 workstation before giving up on Windows entirely

sabrina-unlock repair script: A community tool built specifically for this device. Runs fine on Linux, immediately hits: "Error: device is protected by password", a hardware password Google burned into the chip's eFuses via the February 2021 security update. It's physically etched into silicon. Not bypassable in software.

UART serial console: I soldered wires directly to test points on the board to read boot logs. Found the failed OTA corrupted the boot partition ramdisk. Also found Google disabled serial input entirely in their bootloader, you can watch the boot process, you just can't touch it. I even wrote a Python script to automate keypresses at the exact right millisecond to make sure it wasn't just human error.

USB hub boot: Bought a powered USB-C hub hoping to boot from a flash drive. Requires loading a custom bootloader first, which requires the exploit the eFuse password blocks. Circular dead end.

The hardware is completely fine, the chip, storage, WiFi, all of it alive and responding. The device is being killed by its own security architecture with no official recovery path.

The part that genuinely bothers me: the February 2021 "security update" that burned this password into the hardware is exactly what makes recovery impossible when a future update goes wrong. Google removed the community recovery tools and replaced them with nothing.

I'm in Argentina, bought through unofficial resellers so no warranty, but that's almost beside the point.

Did anyone actually solve this? Am I missing something obvious? Did I do a ton of dumb shit for nothing?