Recover from Boot Loop

Stock and Custom Firmware Development For the UG802.
deadhp1
Posts: 677
Joined: Thu Sep 20, 2012 5:22 pm

Recover from Boot Loop

Postby deadhp1 » Sat Sep 22, 2012 11:35 am

The method below may break your UG802's case and or destroy your device. Use at your own risk. We are not responsible if you hurt yourself or your device.
This method is a work in progress. We are hoping the manufacturer will provide us with a better option
It is possible to recover from a boot loop by opening your UG802 and shorting 2 pads located near the NAND chip.
If rooted make sure that you uninstall the UG802 adb drivers.
Make sure that your UG802 is unplugged.

1)Download Rockchip Batch Tools v1.5 and extract. Also download and extract the firmware you wish to put on your device.

2) Open your UG802 with a case opening tool or guitar pick. Be careful not to break your clips.

3) Locate your NAND chip and the 2 pads next to it. See pic below.
reseting.jpg


4)Short the pads while plugging the UG802 into your computer. Windows will detect a new device.

5) Widows will search for drivers and probably won't find any. You may have to open control panel --> device manager, right click on unknown device, and choose update driver. Install the windows drivers located in the Rockchip Batch Tool folder. If successful you will see a new device listed as RK30sdk.

6)Start Rockchip Batch Tool v1.5 . Select your firmware "update.img" and choose "Restore". You could also choose Update which would format data and user.

7)When complete the status window will reflect Restore Done Success<1> Fail<0> This means that it finished properly.
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userx
Posts: 49
Joined: Sun Sep 23, 2012 6:51 pm

Re: Recover from Boot Loop

Postby userx » Mon Sep 24, 2012 12:35 am

How do you short out the 2 pads? With a paper clip?
How long do you short it out for?
A few seconds or throughout the whole re-flash process?
Did you test this method and were you 100% successful.
Thanks in advance.

deadhp1
Posts: 677
Joined: Thu Sep 20, 2012 5:22 pm

Re: Recover from Boot Loop

Postby deadhp1 » Mon Sep 24, 2012 2:50 am

I tested this method and it works. I shorted the pads for a couple of seconds while plugging in the usb to my computer. I didn't have to keep the pads shorted after it was recognized.

Finlessbob
Posts: 30
Joined: Wed Sep 26, 2012 11:30 am

Re: Recover from Boot Loop

Postby Finlessbob » Wed Sep 26, 2012 12:18 pm

FYI, the 2 copper pads just below the solder points do the same thing. If you wanted to add a little surface mount momentary switch there you could. The case has room for it. But you better have the right solder equipment!

Bob

deadhp1
Posts: 677
Joined: Thu Sep 20, 2012 5:22 pm

Re: Recover from Boot Loop

Postby deadhp1 » Wed Sep 26, 2012 2:43 pm

I'm planning on soldering a momentary switch from an old cd-rom drive onto the 2 pads. Nice to know that there is a second option if I screw that up.

Finlessbob
Posts: 30
Joined: Wed Sep 26, 2012 11:30 am

Re: Recover from Boot Loop

Postby Finlessbob » Wed Sep 26, 2012 5:36 pm

I am also looking at the copper spots on the other side of the board as I think they are run there as well. Just which ones :). It's hard to use a meter and trace them. I bet they are there though.

Now let mejust say. Only guys like you and I that develop and brick a lot need this :)

Bob

eCCoMaNia
Posts: 111
Joined: Wed Sep 26, 2012 10:56 am

Re: Recover from Boot Loop

Postby eCCoMaNia » Sat Sep 29, 2012 5:19 am

hello,
I tried this explanations but I cant make my computer see my ug802, which usb port I need to connect to the pc ? normal usb port or micro usb port ?

deadhp1
Posts: 677
Joined: Thu Sep 20, 2012 5:22 pm

Re: Recover from Boot Loop

Postby deadhp1 » Sat Sep 29, 2012 12:24 pm

The micro port. Just like you're powering it.

eCCoMaNia
Posts: 111
Joined: Wed Sep 26, 2012 10:56 am

Re: Recover from Boot Loop

Postby eCCoMaNia » Sat Sep 29, 2012 5:45 pm

deadhp1 wrote:The micro port. Just like you're powering it.

thank you made it work :D the connection pins were covered with flux after a little straching I made it work :D

terrandroid
Posts: 2
Joined: Sun Oct 07, 2012 6:47 pm

Re: Recover from Boot Loop

Postby terrandroid » Tue Oct 09, 2012 3:10 pm

hmm, those pins don't seem to work for me. tried to do it a couple of times but no reboot .
are there any other ways?

deadhp1
Posts: 677
Joined: Thu Sep 20, 2012 5:22 pm

Re: Recover from Boot Loop

Postby deadhp1 » Tue Oct 09, 2012 3:34 pm

Those are the only 2 I know of that are easily bridged with a screw driver.
Sometimes it can take a few tries...it took me 6 tries last night.
Directly below the 2 solder pads are 2 gold pads that may work, but I'm not sure.
BTW it won't cause a reboot, you need to bridge the connection while plugging the ug802 into your computer.

Viljar70
Posts: 4
Joined: Tue Oct 30, 2012 1:06 pm

Re: Recover from Boot Loop

Postby Viljar70 » Tue Oct 30, 2012 1:21 pm

Where do I get the update.img ?

AndrewDB
Posts: 144
Joined: Sun Oct 28, 2012 5:53 pm

Re: Recover from Boot Loop

Postby AndrewDB » Wed Oct 31, 2012 6:49 am

Thank you deadhp1 for the write up and macro photo detailing this.
Just a note as I am starting to work on the kernel source for the UG802: this simple procedure can probably (once I have tried it myself I'll change that to "certainly") be used to "unbrick" the UG802, by flashing a known working kernel on top of an experimental kernel.

Viljar70
Posts: 4
Joined: Tue Oct 30, 2012 1:06 pm

Re: Recover from Boot Loop

Postby Viljar70 » Tue Nov 06, 2012 12:46 am

Does this Fix help with stock firmware only, or also with Finless 1.4a ROM (Flashed the "hard" way)

I discovered that i only get Bootloop if I use external USB chargers. If I use the TV's own USB to power the device, it boots up, but still restarts occasionally at random points.
I have tested 3 TV's and about 5-6 AC-USB chargers. Maybe a ground problem ?!

About that random reboot.. any idea, is it a problem with software/firmware or is my unit faulty ?!

AndrewDB
Posts: 144
Joined: Sun Oct 28, 2012 5:53 pm

Re: Recover from Boot Loop

Postby AndrewDB » Tue Nov 06, 2012 9:11 pm

Viljar70 wrote:Does this Fix help with stock firmware only, or also with Finless 1.4a ROM (Flashed the "hard" way)
...


It works with any firmware.

Viljar70
Posts: 4
Joined: Tue Oct 30, 2012 1:06 pm

Re: Recover from Boot Loop

Postby Viljar70 » Thu Nov 08, 2012 11:45 am

Flashed the Finless ROM 1.6 and No boot-loop, no crashes and Audio-Video perfectly Synced :)

persian_adonis
Posts: 3
Joined: Sun Nov 11, 2012 1:31 pm

Re: Recover from Boot Loop

Postby persian_adonis » Sun Nov 11, 2012 8:47 pm

First off much thanks to deadhp1, finless bob, and all the others that've worked on the ug802, and taken the time to post their work and help. I'm hoping you can help me out with mine.

Had the jb preview rom runnin perfect, installed netflix restarted and it got stuck on the android logo, eventually going dark. Tried the procedure listed above and it worked...to a point :evil: pc picks up the stick, but when i go to install the driver windows tells me the best driver is already installed, without any other options. I've uninstalled the drivers, restarted my pc more times than i count and am close to gnashing it with my own teeth.

Any help would be GREATLY appreciated.

vanlon
Posts: 1
Joined: Sun Nov 11, 2012 11:23 pm

Re: Recover from Boot Loop

Postby vanlon » Mon Nov 12, 2012 12:57 am

I can't seem to get out of this bootloop. I used this method, everything worked well. I did both a stock and a finless hardway, and still see a second of the splash screen (two penguins, or finless one) then back to the bootloop. Not sure why this isn't working.

AndrewDB
Posts: 144
Joined: Sun Oct 28, 2012 5:53 pm

Re: Recover from Boot Loop

Postby AndrewDB » Mon Nov 12, 2012 5:27 pm

Some PC / notebooks don't provide the power necessary to correctly reflash the UG802 on their USB port (you need more than the usual minimum 500mA that USB ports are rated for). If the procedure described doesn't work, first try another PC or another USB port on the same machine.

persian_adonis
Posts: 3
Joined: Sun Nov 11, 2012 1:31 pm

Re: Recover from Boot Loop

Postby persian_adonis » Mon Nov 12, 2012 8:49 pm

Solved! Tried it on my laptop, which i had used before to flash it (vs the pc which i hadn't), and it worked like a charm. :lol:


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