Ensure a solid, soldered, or tightly clipped connection to the GND pad.
Use a toothpick or non-conductive tool to press and hold the hidden reset button (usually located inside the AV jack or SPDIF port).
Google Verified devices use hardware-rooted trust chains. If the BootROM detects an unsigned bootloader, or if an unauthenticated tool attempts to send commands over UART, the SoC will permanently halt the boot process at the BootROM stage, throwing this exact error to prevent unauthorized tampering. Step-by-Step Troubleshooting Guide Ensure a solid, soldered, or tightly clipped connection
Let's break down the possible causes and solutions for this error:
. It is a security feature that uses cryptographic signatures to ensure that the software being loaded (the bootloader, kernel, etc.) is official and hasn't been tampered with. Android Open Source Project Why This Happens Tamper Detection If the BootROM detects an unsigned bootloader, or
To troubleshoot effectively, we must understand each component of the error string.
Open Device Manager ( devmgmt.msc ). Ensure your serial adapter displays a clean COM port number without a yellow warning triangle. If using Prolific adapters on newer Windows versions, roll back to an older, compatible driver version. Step 3: Configure GXDownloader / Boot Utility Correctly Android Open Source Project Why This Happens Tamper
Locate the onboard eMMC flash chip or SPI flash storage on the PCB.
The error specifically asks you to "check stb uart receive." If you have a USB-to-TTL serial adapter (e.g., CP2102), connect it to the RX/TX/GND pins on the STB motherboard.
Follow these sequential protocols to isolate and bypass the BootROM handshake failure. Step 1: Fix the Physical UART Connection