The key is held by the device manufacturer, which means that only NVIDIA factories are allowed to unbrick the SHIELD TV. NVIDIA designed the USB RCM protocol to only accept signed messages on production fused devices. Getting into APX mode was the first step. The second reason is that it would have made for a boring blog post □. To make things less painful, I soldered a piece of wire to one of the pads and attached it to a pin I can easily ground.Īt this point, you may wonder why I didn’t just re-flash the eMMC and the main reason is that I didn’t have the patience to find the correct signals (CMD/CLK/DAT0) and solder to those tiny pads all clumped up together (I also don’t own any micro/nano soldering equipment so I have to do everything with a standard tip iron). I used a pin to short one of them to the shielding near it and saw the APX device show up on my computer. This seemed like a promising route because I remember seeing some unfilled pads near the eMMC. After chatting with famous Switch hacker he suggested I short out the eMMC while booting to force condition 1. 3 is not an option because we need to run software. I spent some time with 2 by trying to short a random sampling of pads on the logic board while attempting to boot (with no luck). Of these options, 1 is unavailable because the boot-loader is indeed valid (and signed) and the processor dies while already running that boot-loader. A scratch register is written to by software before rebooting.holding some button combination while booting). Some GPIO is pulled to a particular value (e.g.The ROM fails to find a valid boot-loader.According to some reverse engineering done by there are three ways of entering APX mode: This is implemented in the boot ROM (so it can never be corrupted) and uses NVIDIA’s RCM protocol to communicate. On Tegra devices, there is an emergency recovery option called APX mode. Therefore, when cboot tries to setup some device with the wrong configuration, it ends up in a dead-loop. I flashed a DTB (device tree blob) designed for an older version of cboot. ![]() Unfortunately, there was no recovery option available in the console but from the logs I was able to understand the reason why the SHIELD TV no longer booted. I was able to solder some wires to the pins and get a serial console. ![]() A quick probing of suspicious looking pads on the logic board yielded no results but luckily, people in the Linux thread have already found the pins. Some devices (such as the Kindle) even have recovery options available over the serial port. I needed to figure out why the device was not booting and a UART console usually provided diagnostics information. Thus began my journey to recover the device. Even though I have never cared about this device, I was still ashamed at my negligence and felt guilty about creating more e-waste. It turns out that a bad DTB brick was quite common in the community and unfortunately the only proposed solution of “return it to Best Buy” was not an option for me. After following a guide from 2015, I quickly bricked the device trying to flash an outdated DTB file. Wouldn’t the SHIELD TV make a great RPI replacement? It has been out for almost a decade now and surely people have gotten Linux working on it. I had forgotten about it until I had a need for a Raspberry Pi and discovered that they were all still sold out. He worked at NVIDIA and got it for free and had used it only a handful of times before it traveled from his closet to my own. So, in a sentence, THE TABLET IS COMPLETELY DEAD! Hardware problem? Software problem? I don't know, but what I know is someone will respond NOW, LIKE RIGHT NOW, I JUST FINISHED EXAMS AND I WANT TO HAVE FUN (sniff.Last year, a friend gave me his SHIELD TV when he moved. So maybe a factory reset will wake it up, I pressed the VOL-down and power button to get into fastboot and using the VOL-down and VOL-UP button to navigate, I choose recovery mode with the power button, then nvidia logo for seconds, and it went off! Even the recovery mode won't work. ![]() It rarely reaches the OS but when it did, few minutes and it turned off again by itself, now it never reach the OS, only the nvidia logo for a seconds and off. Last thing I remember doing in my tablet was watching some YouTube videos then updating all of my apps from Google play, and while updating the tablet turned off by itself, I plugged in the charger and played with the power button until it turned on, next I closed the screen for a while and then I got back to open it and there was some glitches on the screen, I turned it off and I tried to open it again, and it only reaches the nvidia logo, for a few seconds, and it turned off.
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