Battery Bootloop with eMMC

Hi guys,

I´m pretty new to the switch game but i do have experience with microsoldering and diagnosis of iphones and macbooks. I already fixed a few switches but I´m stuck with this one.

It looks like it has some liquid (coca cola?) spill. Board looked clean except the eMMC had some liquid between the pcb and the chip and there was some under the fan. I did clean both and gave the eMMC a good reflow but the console won´t start. no shorts on any of the caps.

It charges with 1 amp, i get the battery sign and then reboot and repeat. When i disconnect the eMMC i can inject payload and start Hekate. When i then connect the eMMC i can access it with Hekate and it looks ok. After reboot with Hekate i get the Nintendo Screen for 1 sec then it shuts down and doesn`t reboot.

I can’t get it into recovery mode by pressing the 3 buttons.

Any ideas?


If the cause is Cola or some other soft drink then reflowing is not advised, coke turns to a carbon tar at high heat and makes matters worse, it maybe the EMMC wasn’t exposed to this as it’s not uncommon to have flux residue under the IC from factory… that being said, backup the whole EMMC with Hekate in case future failure occurs.

It is stongly advised that you don’t hotplug the EMMC in future and instead use the jig or other, especially if the EMMC IC is Toshiba as they are particularly prone to failure.

This is interesting, can you post a picture of the console info section of Hekate to show fuel gauge/battery stats while the console is plugged in?

Do you see the logo at power on when not going through Hekate and just pressing the power button normally?

Thanks for taking some time to help me

I did of course clean it first with IPA as good as i could and then gave it a medium heat IPA-Flux boil to get it out without burning it. I guess it worked quite well. The EMMC was not recognized at first, but now it is (when hotplugin it). I will read into the backup and how to do it this evening.

I thought that is is not the best way, but that was my only way to find out if the EMMC is still good or not.

Is this not good? could be 0.9 amps at 15V (can’t remember right now. I try to upload a picture later.

Nothing happens by only pressing the power button. I ether have to plug the charger or a USB-PC connection to get it started. But the buttons do work fine in Hekate.

No worries :+1:

I see, then definately make the backup a priority and get the bis keys with biskeydump or lockpickRCM payload just in case.

No it’s not the only way, you best option would be to disconnect the battery/power and wait til you get a jig or to find the needed pins/points to manually put the Switch into an RCM state :slight_smile: if something happens to the EMMC data without having the keys the whole board is scrap

it is good, it’s just a little out the ordinary without boot logos stock boot as far as I remember, when connecting the USB does the current drop to zero before rising to 0.9A?

I see, well when you get your jig, and after getting the info in Hekate, I’d also check it’s not in autoRCM too, if it is disable that.

i will do so :wink:

ok, i will print a jig later on and try. I don’t think it is in AutoRCM. I plugged it into the PC with the EMMC connected an nothing happend.

If i remember correctly, it actually did drop to 0 and then to 0.9/1A and after that the battery symbol came on for a sec or two and then it restarted again.

back again with some mor information.

I did get it into RCM with the EMMC and a jig.

i got boot0 + boot1 and the BIS Keys but i can’t do a full dump. attached are some pictures.

could it really be the EMMC or some missing data on it?

I’m on my phone right now and hope those images are good…

https:// bilderupload .org/bild/947312241-img-20210916-184553

https:// bilderupload .org/bild/3e3a12306-img-20210916-184659

https:// bilderupload .org/bild/836a12334-img-20210916-185901

Yeah I think you have two problems here, one with the EMMC and one with the fuel gauge… and possibly even an SD related issue

Try just getting as many partitions just in case and keep them safe instead of doing a full dump, particularly prodinfo and prodinfof (right click on the partition and save)

Having the keys are good, if you can get the full keys though with lockpickRCM that would be a good call.

You’ll likely have to go through the whole choidujournx/emmchaccgen process to recreate the FW with said keys and put the fw on a fresh EMMC module, depending on how many of the existing partitions your able to recover you maybe able to just slip in just one regenerated partitions and keep all the original dumped partitons in tact depending on what is good/bad which could potentially lessen the chance of an online ban… though tbh I don’t know how much truth there is to this being a risk

i was able to backup some more partitions but failed at “SAFE”. I was also able to get all the keys with lockpickRCM, but I don’t have a microSD card at hand so i will back them up tomorrow. After i got those i will give the IC one last chance and take it off and reball it. I guess there is still crap underneath, that could cause some trouble.

Why do you think there might be a fuel gauge problem? i was connected to my PC with a pretty long cable that doesn’t charge that well, if you are curios about that “-1%” charging.

There was no SD Board connected, so i guess that’s where that error came from?

Thanks a lot for helping me. I learned quite a lot just from this switch alone. The other ones where easy M92 / USB Ports swaps… :wink:

Ah, you might find your able to slip in a generated Safe partition if your not able to recover it following an EMMC reball.

If your planning on reballing the EMMC also inspect the Vias on the modules PCB as they are prone to eroding away in liquid damage cases.

In one of your images it’s reported the battery capacity is 102.7%, this is likely erroneous due to fuel gauge damage, this can be further verified by looking at the battery/fuel gauge stats page though.

Ah it may be fine then :smiley:

no worries :smiley:

yes they do look bad even after IPA… i might give it a ultrasonic bath tomorrow and see if that helps.

can this be due to a 3rd party battery?

I will work a little more on it tomorrow evening now that i get a better understanding of how it works i can concentrate on the EMMC and its board a lot more. I do have a (probably) good donor EMMC board. I could technically rebuild my data onto this one, right?

No but it could be due to external charging if you’ve done that? I don’t recall seeing it reporting a value of over 100% on anything other than because bad fuel gauges but I may be remembering wrong

Yeah you’d just write all the recovered partitions to it and/or rebuild them with one of the two previously mentioned tools using your saved keys if one of the previously dumped partitions is corrupt.

Quick note though, if your connecting another EMMC module to this board be sure to have the jig installed and get straight into Hekate, if the console attempts to boot normally and if the donor EMMC is on a higher OS version it will burn SoC fuse which complicates things

No i haven’t. I will try to get the EMMC problem fixed first an then look into that.

That looks super complicated just looking those tools up… i hope i can get around doing that :wink:

I had to wait 16 hours to reply…

I gave it some ultrasonic cleaning and can now backup everything except SYSTEM. I will probably take the chip off and put it on a different board where the vials aren’t corroded.

Me again.

I reballed the EMMC, same problem. Switched to a different PCB same problem.
I do have a know good EMMC on PCB now and did a fulldump just to test it.

Can you recommend a good tutorial on how to build a firmware? I got all the keys and parts of the old NAND except SYSTEM and SAFE.


Two options, this one

After following either of the guides I would probably write back all of the intact and recovered partitions but that’s up to you, if you do this just make sure your working with the same FW version as reported by your backed up prodinfo partition when opened with NXNandManager (and the correct keys)

Hope that makes sense.