Yep, its weird because I used low melt on Samsung EMMCs and they have been 2 years going strong. One would think the same method would translate to any other EMMC but these SKHynix ones seem to have...real problems compared to other EMMC manufacturers. Were your recalls SKHynix ones too?
My thing now is too wait for the aerosol flux remover to arrive and wait for a recall to come back in lol because I have fixed it with a re-flow so maybe another 3 months!? I won't do anything to it except heat it up a little to soften the flux and then spray the aerosol under neath the EMMC too rule out if its the flux thats the cause or not. My money is on the low melt but I want to cancel out variables where we can.
~Meanwhile, last week I bought an OLED tablet for one purpose only....attempt the Kamikaze! And luckily it was also an SKHynix EMMC so it worked out well in terms of testing this method with consistency within our variables.
I've heard people on here asking how to practise the kamikaze method and its an easy answer imo. I have some Switch Lite donor boards and practised on random spots till I was comfortable. I got lucky and found a spot where there were lines running a layer or two underneath. Exactly what I needed to practise on because I was planning to tap into the Dat0 line on the reverse of the motherboard like
@CarlosCruz did. If I didn't have a donor board, I would find some scrap pcb around and try it on that. Even if it was a RP2040 board! You just want to get to grips with the pressure and accuracy of the grinding pen and your hand. I have to give it to
@CarlosCruz for giving such clear steps on how he did the method and here were my results:
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For the life of me, I couldn't get solder paste to form in the well-like hole. It was frustrating. I tried using some solder on the tip of my iron to dip inside to the point but the line couldn't hold the ball. Too loose it seemed. Solder paste just clumped and didn't form a ball. Might be the paste itself being old as I hardly used it for a year and the casing of it was damaged so maybe oxidation ruined its chemical properties!? Luckily, I saw
@FXDX used a repair pad (ones used for cpu line repairs) to make the connection. I had a bunch of Relife ones in abundance and it was super easy. No heat station needed. Just tinned the exposed line (carefully), put the Relife repiar pad on that line, quick touch or two with the iron, removed the excess tail of the new line I put in and then checked the connection on my DMM. Solid strong 0.710v. Solder masked it all and then was pretty much done with the Kamikaze. First time is always rough, same with the first time re-balling, but now I know what works for me. Next time will try to make a more even 'drill'...maybe wider and more symmetrical but I think I can stick with the Kamikaze in future.
The results were great too. The EMMC backup of the NAND had time of 36min 17s. Never had that on a SK EMMC before. Those are usually Samsung backup times. Benchmarks all passed too and glitch timing were quick (2-5 seconds, although I use mosfets and pull down resistors so they were glitch timings generally are a non issue for me, but still quicker than before regardless.)
I have ordered some smaller tip bits for the grinding pen so I can have a bit more accuracy but thank God it was good result. (kapton tape around so debris doesn't go too far away and its honestly doable.) I think Kamikaze is the most reliable post mod method so, my thought process is, by tools for it (like I did for the re-ball method) and get good and better at it. But not everyone will have the same thoughts on this but to each their own.
