Vizio M422i-B1 boot loop.

[lookimback]

I got this from a friend and he said it had been unplugged during an update and when plugged back in it was stuck in this boot loop. It gets to the V logo, then the panel cuts off and it starts over. During this, the backlights and secondary voltages always stay up, panel voltage does cycle and indicator goes out. Checked all regulators, all output correct voltages. Main board (XECB02K0170004) has a Toshiba EMMC. Nobody seems to have preprogrammed ones. Anyone know of reset methods for these?

[ducky29]

Re: Vizio M422i-B1 boot loop.

Contact vizio and ask them for the firmware.

[lookimback]

Re: Vizio M422i-B1 boot loop.

Contact vizio and ask them for the firmware.

What I read on their website is that VIA TVs are only updated through the internet.

Edit: It's certainly a good suggestion. I opened a support case with Vizio. We'll see what they say.

[lookimback]

Re: Vizio M422i-B1 boot loop.

Here's the response I got from Vizio support. Basically generic, nothing model specific, and none of it worked. Maybe some of this may be useful for other models we encounter in the future though. At least I got a quick response. I emailed them back asking about the firmware and the possibility of updating via USB. We'll see what they say.

I apologize to hear you are having difficulties with your VIZIO TV. I would recommend performing a power cycle on your TV and re-seat all of the devices that are connected to it. Please follow the steps in this order:

1. Power off the TV.
2. Unplug the TV from the outlet.
3. Disconnect all devices from the TV.
4. Press and hold in the power button on the side or back of the TV for 30 seconds (while it is unplugged from the wall).
5. Release the power button.
6. Plug in the TV.
7. Reconnect all devices.
8. Power the TV back on.

Then attempt a factory reset on your VIZIO. If your VIZIO has a menu button on the remote then do the following:

1. Press the Menu button on the VIZIO remote
2. Select the System option
3. Select Reset and Admin
4. Select Reset TV to Factory Defaults
The TV will restart and begin the initial setup again.

If your VIZIO remote does not have a MENU button then please follow these steps:

Please locate the buttons on the side of the TV, you should find 4 of them. The bottom two would be input and volume down, these are the two we need.

You would need to press these two together for 5-10 seconds, until a bar appears on the top of the TV. Then, you need to press the input button (the bottom button) for 5 seconds, until the screen goes black. This would cause a factory reset to the unit.

Once this is completed, please follow the prompts that get displayed to set the TV up once more. You will need to re-pair your smartphone or tablet using the VIZIO SmartCast application during this.

I would also recommend making sure that this issue is affecting multiple devices/inputs including the onscreen menu on the VIZIO or built-in apps.

If your VIZIO is within the first 12 months of ownership then please respond with the following:

-What devices do you have connected to your TV?
-What types of cords or cables are being used to connect them?
-Is the issue visible on all inputs/devices including the VIZIO onscreen menu?
-The serial number of your device
-A copy of your receipt
-Your physical address
-A valid contact phone number
-A photo of your full TV, powered on, with the issue present

If your VIZIO is outside of the first 12 months of ownership (& not purchased through one of the select few retailers like Costco or HSN) then per the troubleshooting we have completed on your VIZIO, it is in need of replacement. Generally, the cost to repair is beyond economical and it is more cost efficient most times to purchase a replacement TV. However, if you would like a quote on parts/labor for repair I would recommend contacting someone local.

[lookimback]

Re: Vizio M422i-B1 boot loop.

Well, at this point I'm pretty much convinced the eMMC has failed. After a lot of research, I attempted to reverse engineer the pinout and see if I could extract the firmware image. I was able to correctly identify CMD and CLK based on their location and by viewing the waveforms on my scope. I mistook reset for VCC, because it was 3.3v and in close proximity to where VCC is on the chip. Looking back on it, I should have known because it was going through a 4.7k resistor and the trace was too small. I couldn't get the data lines right either, but that's because my card reader wouldn't work in single bit mode. Trying to guess the correct 4 data lines, and in the correct order, is nearly impossible.I picked up a Transcend RDF5 USB 3.0 SD card reader from eBay that will work in single bit mode, so next time it will be easier. Anyway, I decided to pull the eMMC and dead bug it. I got it all wired up, but can't get anything off of it. Windows 7 recognizes it as an MMC, but crashes as soon as I try to access it. I tried EaseUs data recovery and it said it found a JPEG, but then Windows decided to crash before it could complete the scan. I figured Linux would work better, but no such luck. I tried CloneZilla, but really couldn't figure out how to use it. Tried dd, and just got I/O errors. It was recognized as an MMC, and I had mmcblk0, mmcblkoboot0, and mmcblk0boot1 in dev, but nothing could access them and they wouldn't mount. I tried the Transend card reader which does work in single bit mode, but I had the same results with that. Test points are all on the back of the board, and I've identified them in one of the pictures. VCCQ and VSSQ are tied to VCC and VSS, so no test points for them. I have a new eMMC coming from China. I'll have to buy a board to dump the firmware from. Hopefully that will go better. Thinking about it, why would someone unplug a TV during an update unless it had froze up. I'm thinking it died during the update, but, I was getting the V logo, so at least one of the boot partitions was readable in the TV. Not sure why I can't get anything off it. The only connection I didn't make was to VDDi. I'm not sure if I needed that, maybe I'll try that tomorrow if I can find a 1uf cap.