PROJECT: Reviving a Hard Bricked Kyros

lfom

Senior Member
Developer
Sep 12, 2011
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Background
..."Soft Recovery" mode doesn't seem to work in all "brick" cases. When the Coby screen doesn't turn on at all "and" Droid Explorer or Disk Management don't detect the Coby "and" the soft lights shut off after 7 seconds......you're Coby is in a "HARD" brick.

There are some users with "hard bricked" Kyros: tablet will remain on only while holding the power button, during this period the touch buttons will remain light. Buttons will go off as soon as one releases the power button. If the power button is also pressed for a long time (~10 seconds), it will also go off.

There is a similar "hard brick" with tablets very similar to Kyros, known as HeroTab/DroPad. They found out that it's possible to revive the tablet using a "SD boot", when the internal NAND content is bypassed or not needed.
Tutorial with solution is here:
[GUIDE] Revive your dead tablet - SlateDroid.com
Long thread with hardware details (although not devoted to revive a tablet) here:
[DEV] Custom kernel for Dropad/Herotab - SlateDroid.com


Facts:
1. Some Kyros tablets exhibit "hard brick".
2. "Hard brick" is related to NAND problems.
3. Similar tablets (almost same hardware) with similar symptoms were successfully revived, using a bootable microSD card that re-flashed NAND.
4. It is possible to put smdkv210 (CPU board used in MIDxx24) to boot from either NAND or SD.
5. Not all Kyros have the same internals (ex. MID1024 tablets may have MID1025 boards or MID1024N boards, same goes for 7024 and possibly 8024).

Questions:
1. Is there a simple way to determine if a Kyros is "hard bricked", i.e. fully working besides a faulty NAND?
2. It is possible to have console (simple TTL terminal) access to smdkv210 boards, it's also possible with Kyros? How?
3. Is there a way to change a Kyros from NAND boot to SD boot? How?
4. Is there a working bootable image (u-boot-sd.bin) for Kyros? Universal or one file is needed for each model?
5. Finally, is it possible to revive a "hard bricked" Kyros? How?
 
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lfom

Senior Member
Developer
Sep 12, 2011
1,386
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Edited 2011.10.15

1. Is there a simple way to determine if a Kyros is "hard bricked", i.e. fully working besides a faulty NAND?
Open your Kyros, and short-circuit NANDS pins 7 & 8 while you hold power button pressed. I may go on with the screen all white. Release power button and remove whatever you've used to do the short-circuit. If your tablet remains on then probably it's still working. (Ref: Arlic)

It seems that in some cases (maybe due to a non-working/dead NAND), Kyros will boot from external microSD without the need of opening it and short-circuiting pins 7 & 8. It was reported more than once for MID7024 models (megalex and theNige). You just need a specially made microSD in the external slot (see below).

2. It is possible to have console (simple TTL terminal) access to smdkv210 boards, it's also possible with Kyros? How?
Yes, it's possible, connecting some wires to the smdkv210 board (Ref. slatedroid forum forum - Asure/mg3100) found in MIDx024 tablets. It's a risky procedure since the pins are very small and close to each other. Maybe it's also possible to use some pads in the main board, but it isn't documented so far.

3. Is there a way to change a Kyros from NAND boot to SD boot? How?
Yes, there is. So far the only known way is to short-circuit NAND pins 7 & 8 while turning one the tablet. It's also possible to change some smdkv210 board resistors/wires (see slatedroid thread above for more info), but it's not a good solution for Kyros since resistors are too small and there is a high risk that you may break something else or simply won't be able to revert it. If there're pads in the main board for these connections like the ones in Herotab/Dropad boards, then it will be much easier.

4. Is there a working bootable image (u-boot-sd.bin) for Kyros? Universal or one file is needed for each model?
Yes, the same u-boot used for Herotab/Dropad resurrecting firmware can be used with Kyros. The only problem is that it's made for tablets with resistive screens like 7024/8024. It will boot 1024, but a proper ROM/firmware has to be used to actually flash NAND/microSD for a fully working tablet.

5. Finally, is it possible to revive a "hard bricked" Kyros? How?
Yes! Arlic was the first one to find it using a MID8024. So far, his procedure was tested with 7024, MPMAN827 and 1024. For success, a correct firmware is needed (the ressurection firmware only revives the tablet, the correct one is needed for a fully operational unit). For this reason, it seems that some old MID1024 tablets actually use a 1025_v4 board that may brick if used the official firmware, so a working ROM for these models is yet to be found.

PS: microSD card with resurrecting firmware used in the external slot must be 4GB or bigger! (found by SampNeves)

If you still have questions, ask it in this thread and I am sure someone will try to help.

Thanks for everyone who helped and shared what has been found. Props go to Arlic for trying it on smdkv210-based Kyros and sharing it! ;)
 
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lfom

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Sep 12, 2011
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Got that PDF too. It explains how to choose between NAND and SD boot, but it needs to change wires (or resistors) in the board. That how they got access to NAND boot in the SlateDroid thread about a custom ROM.
Regarding Kyros, it seems that the board doesn't have any labels for the pads (8024 pics from nefirim):
http://www.androidtablets.net/forum...-7024-gingerbread-firmware-55.html#post131728

I don't wanna mess with the CPU board as the soldered items are too small. If we are able to find out OM1-OM2 pads in the Kyros board, then we have a starting point... Until then, only assumptions I guess...
 

nefirim

Senior Member
Developer
Sep 10, 2011
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If anyone has a board/tablet they're willing to spare or don't care about, I can try and do some testing to see if I can get a serial connection on it and then beyond that, if there is a way to SD boot. I unfortunately do not have the money to buy another and make this one my testing one.
 

lfom

Senior Member
Developer
Sep 12, 2011
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So, no one knows how to get a console connection to Kyros 2nd gen boards?

It seems that hard bricking may be related to a hardware failure, when the system tries to write to the NAND. I've read some reports when people bricked tablets simply by trying to flash the official stock firmware. Maybe a design defect? If so, it'd be very dangerous to try any ROM flashing using any smdkv210 based Kyros.
 

nefirim

Senior Member
Developer
Sep 10, 2011
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also I found this little http://db.tt/hbx3ZTFa jewel after some google-fu. Its the full data sheet/manual for the S5PV210 (Thanks to the folks at Slatedroid) which does include the memory address map and also the pin outs, meaning we can now find the OM1 and OM5 needed to get SD boot. granted this just shows it for the bottom of the processor which is covered but it does allow for a more educated guess as to which of those pads on the back of the board go to what.
 
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lfom

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Sep 12, 2011
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This is nice. If we are able to get a direct terminal connection to the smdkv210 board it would be half the problem solved. If it only needed USB then much better.
 

lfom

Senior Member
Developer
Sep 12, 2011
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Unfortunately, not... I sent a PM to someone who reported here in this forum that was able to complete a terminal connection to a MID7024 but got no reply so far. Until we're able to do this there isn't much we can do besides blind trials. :(
 

Arlic

Member
May 13, 2011
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9
HOW TO UN-BRICK A "HARD"-BRICKED Coby MID8024.
Yes, I did it. I un-bricked my Coby 8024. While installing the gingerbread ROM "C8lean 1.1 meshed.rar" by "elemist2" I "hard" bricked my Coby. A "hard" brick is not the regular recovery mode(pressing power button and HOME/SILVER button at the same time) that the Coby uses to install new roms. It is a state that the Coby goes into when the NAND becomes corrupted for some reason. When this happens the Coby appears dead to the outside world, even to the USB and HDMI ports. The NAND appears to have only one purpose and that is to hold the bootloader, see the thread "Creating a proper system layout" by "fonix232" at SlateDroid for more information. BORING!!!! Ok, onward.

Anyway, you can unbrick a mid8024(maybe 7024) with very little work, but you have to open your Coby for this to work. This method is only for a "Hard" bricked Coby8024(7024). If, you have a regular "soft" bricked Coby first try the regular method before attempting this one.
Also, I didn't do this first, "vinylb" at SlateDroid did it back in February. Look for the thread "How to unbrick your Coby MID7015". I used a slightly different approach.
You will need the following:
1)VERY----VERY small screwdriver or metal probe.
2)The original Coby ROM. Once you get the thing working you can always throw another ROM on it.
3)MicroSD card, just big enough to dump the ROM.
4)A opened Coby .
The Fun Part.
1)I used a 8G microSD card that was partitioned with the file "u-boot-SD.bin.mid703v3.mm". I won't bore you with the details because if you are reading this article you have exhausted all other options.
Just put the original Coby ROM into the FAT32 partition. Put the microSD card into the Coby external slot. SIMPLE!! HARD PART COMING UP!!
2)Ok, if you don't know where your NAND is stop reading now and go find out. With the Coby open and the microSD card in the regular external slot you have to take that VERY small screwdriver and stick it between pins 7 & 8 of the NAND chip. You just have to short pins 7 & 8,how you do it is up to you. Simple. :)
3)With pins 7 & 8 shorted you now just do a regular plain-Jane recovery mode procedure. Simple.
I just shorted pins 7 & 8 on the NAND chip and did power button and home button at the same time.
The Coby screen turned bright white(all white) and I just let go of the power button and something "wonderful" happened. The Coby stayed on!! Yes, after 3 weeks of turning off whenever the power button was released it "stayed on". Yes, "something wonderful" happened.
I held the screwdriver against pins 7 & 8 until the Coby turned off by it self, which was about 4 minutes....give or take.
I flipped over the Coby, remember its still in 2 pieces, and pressed the power button, and .....and....
Saw "COBY". YEPPIE!

WARNING!!! I tried over 20 different recovery methods from over 4 different forums before I tried this. The Coby never gave me any sign through screen, USB, or HDMI. Just soft menu buttons lighting up with the power button press. It was DEAD! I didn't have any other options. Nothing else worked. I had nothing to lose. If, you have any questions just ask before attempting this method.


Any comments, suggestions, money, gifts, or whatever can be just posted to this thread.
Thank you for taking the time to read this article.
Bye...
Arlic
 
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