MK908ii (Geekbuying) Bad NAND

[TheStonedDog]

Hello!

I recently purchased a MK908ii from geekbuying.com. When I got the device it booted fine. I went ahead and flashed Finless's MK908ii 1.4a ROM. It booted fine as well. I then proceeded to load some of my favorite apps. When I went to reboot the device it hung at the boot screen. I couldn't get the device to boot after a few power cyclings so I decided to reflash the ROM. I couldn't get a full IDB erase but I read in Finless's readme that he had the same issue and as I was flashing the misc.img it should be ok.

At this point I could upload the ROM files to the device but it would fail on the verification process around the 4K mark. I connected it to the TV and I could see the recovery do a wipe then reboot. I tried a few more times to flash the ROM erasing in between even though it looked like it was failing with a message of "Total(0) Current(6)" appearing. After that I would only see the Tronsmart logo on the TV when booting.

I decided to flash the stock ROM and now the device will not boot on the TV at all. Also at this point the device would not be recognized by the computer. I managed to locate the NAND reset pins on the IC (different pin location then other board NAND chips) which got me into the MaskROM mode. I would then issue an IDB erase which would still fail but the device would be recognized loader mode instead of MaskROM. I then try a ROM flash and it would still fail at the verification process again. Sometimes it would make it to the 54K mark and sometimes fail right at 0K but the majority of the time its at the 4K mark. This happens with both the Finless tool and the RKBatch tool and with both stock img ROM and Finless 1.4a and in both loader and MaskROM mode.

I am experienced with Android having many devices. I have a MK808B that I flashed a few times with the same computer setup and I have had no issues with that device.

I'm starting to think I have a bad NAND IC. Any other advice ? Should I contact Geekbuying about the issue ?

[jdamore]

Wish I could be help. The only advice I can give is to try a different USB cable. The one supplied with my unit is a piece of junk and fails when flashing.

Help that works for you.

Jeff

[riversdirect]

I would say try re-flashing on a different computer with the latest rockchip USB drivers. I noticed i needed to update my rockchip drivers when I went from the 3066 to the 3188 chip devices. Its worth a try but sounds like you could have a bad device too.

Good luck,
Rivers

[TheStonedDog]

Thanks everyone for the responses.

I tried three different USB cables and different USB ports on the system. I only have one computer that runs windows as my other systems run some unix variant. I did remove the driver and reinstall when I did the first flash on the MK908ii to make sure nothing from the MK808B driver would interfere. I used the same setup when I flashed the first successful time so it should have been good.

One thing I did notice is as I tried to flash each img file on its own and I could get every file to verify except the large system.img. I'm guess the location in memory that the system.img file goes is corrupt.

I'm going to contact Geekbuying to see what they can do.

Thanks again to everyone.

[TheStonedDog]

Just a follow up.

As I suspected the NAND memory was damaged. I replaced the NAND memory myself with a new and better brand of NAND.

I fired up the stick and I was able to successfully flash Finless 1.4a. Its been running for a few days now and I loaded a fair amount of content without an issue. Everything looks to be stable now. Yay!

While I was able to resurrect my MK908ii I would not say this is a beginner job or even intermediate. You have to be well versed in SMD soldering and have the correct tools. Even with those tools it still took a few tries. I just hope that if others run into the same situation this information can help them diagnose the problem.

To Geekbuying's credit they did respond to my emails and offered quite a bit of support from two different people. In the end they did offer to exchange the MK908ii for a new one before I managed to get the MK908ii working again. For the cost of the NAND memory and my time verses the time/cost to send back the damaged unit then receive a new one it made sense for me to fix it.

I hope this helps others.

[FadeFx]

AW: MK908ii (Geekbuying) Bad NAND

Just a follow up.

As I suspected the NAND memory was damaged. I replaced the NAND memory myself with a new and better brand of NAND.

I fired up the stick and I was able to successfully flash Finless 1.4a. Its been running for a few days now and I loaded a fair amount of content without an issue. Everything looks to be stable now. Yay!

While I was able to resurrect my MK908ii I would not say this is a beginner job or even intermediate. You have to be well versed in SMD soldering and have the correct tools. Even with those tools it still took a few tries. I just hope that if others run into the same situation this information can help them diagnose the problem.

To Geekbuying's credit they did respond to my emails and offered quite a bit of support from two different people. In the end they did offer to exchange the MK908ii for a new one before I managed to get the MK908ii working again. For the cost of the NAND memory and my time verses the time/cost to send back the damaged unit then receive a new one it made sense for me to fix it.

I hope this helps others.

Youd better mention what exact nand chip u soldered in there, afaik the kernel needs to be compatible to it as well...

_________________________
tapatalked from GalaxyS3

[TheStonedDog]

Youd better mention what exact nand chip u soldered in there, afaik the kernel needs to be compatible to it as well...

As they say in some parts "this is not my first rodeo."

There are several factors to finding a proper replacement. The case size/type, voltage, pinouts are some of the physical attributes to match. Memory is not just about the amount but also how the memory is partitioned and addressed. It took some research to find a local sourced part that met this criteria.

The original NAND was labelled Foresee NCTSTS76-08G. I could not find a much on this part other then a PDF from a parts supplier and it was buried in the document among hundreds of other parts. There is very little information in the listing. What it did have in the short description was the part case size (48TSOP) and the memory confiuration (64Gb in a 8G x 8 configuration).

I found a couple of photos of other android stick's NAND memory. While the NAND in those shots were of a different labelling the format made it a safe bet that the manufacture used an IC with the same configuration. Looking at the datasheets of those NAND parts I saw the memory configuration was the same as the Foresee part so I assumed the rest of the missing specs, namely the pin outs and voltages, would be the same as the Foresee part.

The other issue is there are a couple of manufacture variants of the 48TSOP case size. Using the datasheet of the known part part above, which has dimensional specs, along with a digital caliper measuring the Foresee part I was able to confirm which 48TSOP case would be a match.

Armed with a full set of specs I checked with my various part suppliers for a match. What I came up with is this part:

Micron Technology Inc.
MFG P/N: MT29F64G08CBAAAWP:A TR

The part was sourced from Digikey. P/N: 557-1490-1-ND

Luckily they had cut tape in stock so I went ahead and ordered.

The part is working fine. I partioned the NAND using the Finless 4G parameter file. The full memory is being reported in the settings. I loaded a fair amount of content to come close to the max to make sure the memory was being used correctly and fully.

If I were to guess what happened it would be this. With Foresee not being a well known manufacture they are actually paying for a run of parts from another manufacture but skipping the varification process to save money or they are buying leftover / QA failed stock from a manufacture. They in turn sell at a slightly below normal price to board assemblers to keep their costs down. They hope there are enough good parts in the batch to overcome the cost of the failed parts. These are the parts being used in the MK908ii and probably others. I have seen this many times.

[Finless]

Question....

I also cannot find much on the Foresee NCTSTS76-08G. Specifically which pins to short to get inti Mask ROM mode. We have a few people now stuck and need to know how to get it into Mask ROM mode.
If I could find a damn spec sheet for this chip I would be able to help folks but I cant.

Your post said they are different pins. Can you tell me which they are?

Bob