I would be tempted to take the measurements anyway, it isn’t going to hurt anything, and then we have more info even if it ends up not being useful.
If we are working on the theory that it is gunk shorting out something under the chip, then an ultrasonic clean should help?
What I still dont understand, assuming that the emmc is the cause of the short. Why does RCM lock up with the emmc removed?
ok, ill give it a minute in the ultra sonic cleaner and take some readings and post them.
im not sure about the RCM, i dont know that much about the firmware mods etc yet.
i just gave it a minute in the ultrasonic cleaner and it didnt change anything.
I took some readings using Insomniacs as reference using diode mode, (red probe on gnd)
all readings matched to within around 20, apart from the 5 vias in the picture.
I haven’t checked, but those lines probably correlate with 1V8PDR…
Apply flux around the IC and give it a flux boil at 180/200C low to medium air then flood the IC in IPA and again with your hot air now at 150C flush the flux out, repeat the IPA process several times, finally one lasts rinse in IPA
Connect the EMMC to the mainboard again and measure the shorted rail once again and see if the value has changed from where it was last, if the resistance has increased it means your getting somewhere.
Ordinarily I’d recommend pulling the IC and reballing but if you have no experience doing so or don’t have the equipment to do so then this isn’t the place I’d start as the board has so little thermal mass it’s easy to over expose the pads mask on the PCB which then can cause the chip to tilt and short things out which in turn kill the IC or corrupts the data preventing repair.
It’s also entirely possible the IC is dead but if your readings change somewhat then there may be hope 
Severance, just to confirm you want me to give it another flux boil? I have already tried this with no change in results.
Just above the picture i had cnnected the emmc to the mainboard after the flux boil and it was still reading very low 30 ohms.
I am competant in changing ICs etc, but have never reballed anything, i mostly work on laptops and they dont have that many BGA chips
Right, your readings did change for the worse afaict which suggests there is somethings moving about below the IC.
You measured 78ohm previously right?
The IPA rinse is pretty cirtical after with the hot air as flux gets brown tacky following activation and will hold on to the corrosion, the idea is to activate it to try to dislodge the corrosion then use the IPA to flush out the flux and the corrosion together in combination with heat.
Definately something to get acquainted with but I wouldn’t start with this IC, you’ll need stencils and solder paste 
Ok i see, also after the dip in the ultrasonic cleaner, the readings were about 50ohms.
Im using amtech flux, would you suggest rosin or anything else?
ok ill give it another go,
with the IPA would you completely soak it for a period of time.
i dont mind investing in some stencils and a holder, at some point i will have to,
i was going to ask if you find it better to use solder paste or balls
I’m just guessing but imagine that change was more as a result of thermal change more than anything as I mentioned earlier.
Amtech is fine, you can also mix some up with IPA if you want to thin it out, though it’s a pain to mix, you can put it in a plastic bottle with a ball bearing to make it easier. Cheap Liquid flux I do not recomend, I got a cheap one years ago and it smelled like acetone 
not initially, so after the flux boil I just flood the IC in question then using the hot hair I heat the IC, you’ll see it bubbling away, when it’s evaporated add more and repeat, during the process you’ll see flux residue around the edges of the IC which it’s pulling out, you can even saturate the area as well as a cotton swab and run round the edges of the IC during this process which helps pick everything up and keeps the IC saturated for longer with IPA.
You can also dilute the IPA with distilled/deionized water which stop it from evaporating so fast, trouble here is, EMMC ICs are particularly sensitive to water so I don’t use it in these cases.
I prefer paste for ICs which are below the Ram size and everything above I prefer preformed balls
ok thanks for the information, ill try this and report back
So all the vias you tested as low are actually the same rail.
This is where it goes under the chip:
Given that, I would concentrate your cleaning on that top right area and maybe see if you can get a view under there with a microscope? That capacitor is on that line also, so maybe test that too?
The one point in the middle is harder to get to of course…
i gave it another flux boil and rinsed thoroughly with ipa, and now the measurements in diode mode on the emmc on the 5 points mentioned ealrier, is lower .006
and when connected to the mainboard, at teh 1.8v coil it is reading just 8ohms now
Insomniac, its interestig they are all on the same line, it is looking like its the IC is short,
At this point it’s either a sugar based drink and the heat is making matters worse, or the controller within the IC is dying…
You can pull those caps on this rail at this point, just use your soldering iron to whip them off just to ensure they aren’t the cause
at this point I’d attempt to recover the data on PC or not recommended on another known good board in Hekate, try to get the prodinfo and prodinfof partitions first as well as your BIS keys
you wont believe this guys, after leaving the emmc and mainboard for several minutes, i measured again with emmc connected, and the readings were quite erratic,not really staying anywhere going from around 8ohms to 5k ohms, but not staying at a low resistance
i thought what the hell ill just try plugging it in, and it started to fast charge!
so i plugged the screen, backlight etc in and it did power on to home screen, i cant believe it, how is that possible
ill have to keep an eye on it for a while,
great, if it’s unpatched back it up straight away 
This IC can possibly fail later on down the line so definately do this just in case
Either the EMMC was warm/hot when you took the measurments prior or the power on has cleared the short which it was likely not able to do prior due to the liquid/corrosion.
yes deffinetly the flux boil has done somthing, great advice.
I am a noob when it comes to the patched/unpatched, firmware hacking side, do you have a quick guide anywhere i can read to back up the emmc?
thanks again both of you for helping,
if you type ismyswitchpatched on google first link, type the serial number (can be found in system settings on switch) if it says it’s unpatched, then you can load Hekate payload with tegraRCMGUI
you will need the jig to go in the joycon slot to get into an RCM state, I do not recommend disconnecting the EMMC (to get into this state) then hotplugging the EMMC when in Hekate
Or you can short the correct pins out on the joycon connector, your choice
In the meantime, I would turn the unit off, and disconnect the battery until you have a jig, which you can get on eBay for couple of quid.
Full guides here
https://nh-server.github.io/switch-guide/
Awesome! Definitely worth getting a backup if you can, as then if it does fully fail in the future you can restore it onto a replacement emmc module.
@Severence ok great i will look into this, thanks again for the info. if it is a patched Switch does that mean i cant run any payloads on it, and not be able to back it up?
@Insomniac yes best to be safe, so the back up can be written onto any emmc once i have a copy of it on PC?
You can still back it up if it’s patched by using a PC, it’s just the process is a bit more involved
Right, if the backup is 1:1 of the original EMMC, if it’s missing some certain partitions you’ll need the BIS keys to regen the FW
ok, i just checked and the serial starts with XKJ, so i think its a patched Switch
yes thats good to know, it is ab it annoying how they are tied to the soc.
