Hey guys,
I know this thread is a little bit old but I'll try to give in my 2 cents maybe someone here may find it helpful
So I come from background where I do around 20 bga reballs per week, so I do know a thing or two I guess about this although my knowledge on Samsung platform is relatively low compared to an iphone logic.
So to begin with replacing the emmc chip alone is not enough as you'll need a programmer box which connects to a jtag interface which is able to rewrite the initial files like bootrom to the emmc. You can find these boxes at any prominent gsm repair shops; boxes named such as RiffBox or Z3X Samsung box are the best I found recently.
Having said that before any repair is attempted by mainly removing the flash chip it is imperative to try to resurrect the phone using these said boxes, to try to find whether or not the NAND chip is actually detected. As one may have simply installed a ROM which is not compatible with the phone and all that is required is to rewrite the bootrom files. If the NAND (basically the same name as a flash chip) fails to be detected then obviously something went wrong and it either could be the NAND is burnt inside, or the NAND has some cracks under its critical ball pins or even may be a problem that the main power management chip inside the phone is failing from supplying usually around 3V to power up the NAND.
The emmc chip at least found in a samsung is a 14 by 14 pins which only about 1/3 of it's pins are critical, the rest are dummy and do not worry if they eventually get removed, while removing the chip or cleaning the board after desoldering prior installing the new chip.
Some tips on reworking:
- Always cover critical glued components like CPU + POP (package on package) RAM, baseband processor usually XGOLD found in Samsung.
- Clean surrounding chip glue before attempting to remove by giving around 250C of heat and with a needle scratching the glue around
- Do not exceed more than 350C to remove the actual chip to prevent more damage to the built in tracks inside the motherboard.
Last and not least a schematic for your phone would always be a lot of help to help you detect what voltages are missing on bootup to make sure that the boot up sequence is starting fine and also the relative points of each pin under a chip while knowing which pins are critical and which are dummies, or NC (not connected)
If you need any help you can always message me and I'll try my best to answer your questions.
Regards,
Ryan
While emmc chip got like 20 important pads to solder (out of even hundred, when most are there being N/C) it is still BGA. A ****ass small BGA covered with glue. That would require someone really experienced with reworking such things. I do not know the prices but I would be prepared to pay even 100$ or more for such job, done right.
That from HW level. From SW+HW look: in theory there should be no trouble with properly swapped emmc ic from other phone. But you shall not forget about the said 0.01%, maybe more - reworking such chip might have influence on its content (I might be wrong) + GS2 had the emmc hardbrick bug - how did it die?
Please let us know how did it go.
Oh and btw - there must be companies working on such data recovery with proper HW to wire up to the unsoldered chip with sort of socket or other hackaround - I'd lookup there.
0,1% of chance .. playing with Samsung EMMC chip = bye bye phone . look around forum or elsewhere 100% of bricked is due to it .
Question : what make you confident to say that your internal memory is good ?
to remind : it is also your phone flash chip which manage boot sequence and all . don't forget it .
every time I tried with hot air , I removed chip with missing pads cause of glue under chip which make hard to remove .
why not to give a try ? have good luck
Hi Ryan,
My son's galaxy s3 i9300 was inadvertently given a spin in the washing machine...
Hello everyone,
this thread seems to be what I've been looking for. My Siemens A31 got some water from a torrential rain while it was on. When I got to removing the battery, the phone was already off. I dried all accessible parts but I did not have the necessary torx screwdriver, so some water stayed inside. It was Friday evening and I got the screwdriver no earlier than on Monday. There was some corrosion in the phone, of course. It could not be turned on and subsequent cleaning with alcohol and even ultrasound improved only the look of the main board, but not its behavior. The only sign of life was that it seemingly recharged the battery while connected to the charger.
I have asked several repair services and people and I am quite confused whether it is possible to recover the data by soldering the memory chip into another A31, a functioning one of course. Last time, I asked a laptop service and I was told it is impossible, not just because of the difficulty of soldering a BGA chip. They told me it would not work because the phone would get blocked due to IMEI mismatch! This was surprising for me. If it is true, it implies that the IMEI is stored in both the flash memory and some other chip. I was unable to find any evidence for such a claim on the Internet.
Can anyone tell me if the target phone with replaced flash memory will actually work, assuming the memory is functioning? The video referred to by yiannos50 suggests it may really work. Anyone else has tried it? Two people in this discussion were about to do so.