Hacking Need help with Picofly Switch Lite (==* CPU always reach BCT) - What could be wrong ?

Merihel · 2026-06-24T23:32:48+0100

Hello everyone,

I'm trying to get the Picofly mod to work on my Switch Lite.
When booting up, I have the yellow light : two long, then one short (==* which means "CPU always reach BCT"). Switch boots on HOS normally.
I knocked out a SP2 capacitor but I had two other dead Lite mobo and I took one from here.
I tried to make sure my soldering on SP1 and SP2 was right, and saw something around 10ohms with both caps when testing with the multimeter.

Is there anything I could check to make sure the soldering is good ?

What I already tried :
- Flash the firmware (fw_2.73.uf2) multiple times
- Tried resoldering multiple times to make sure it was as clean as possible
- Tested values of capacitors using the solder points (and even on the end of the CPU flex cable)

Am I doing something wrong ?

thesjaakspoiler · 2026-06-25T03:57:51+0100

Those values seems fine.
That error message means that the mosfet doesn't get triggered, isn't connected to the capacitors or the mosfet/flex cable itself is broken.
The A,B,C,D connections are likely fine as the picofly would be complaining about those before it throws the BCT error at you.

Did you put in the cable the right way and all the way?

Another possibility might be a broken mosfet or flex cable but that doesn't happen that often.
For the cable that I had at hand, the middle 2 pins go to the gate of the mosfet.
The drain and gain of the mosfet go to either side of the sp1/sp2 capacitors.
There are different flex cables out there but the finest line is what switches the mosfet and this is the gate.

Merihel · 2026-06-25T22:38:04+0100

Hi, thank you for the explanations !

The cable is all the way in and there's no way I can push it further.
I'm not sure how to test if the mosfets are good. Do you know how I could do that ? Continuity mode may not be reliable enough, right ?
Here is the model of Picofly I have, if it helps.

If I order a new flex cable, do you know if that V1/V2 pinout could work with my Picofly model ? (I attached an example).

Thanks again!

master801 · 2026-06-25T22:59:15+0100

Use diode mode instead of continuity mode.

Continuity mode is basically diode mode, but checks if it's relatively low value -this is almost near 0- and then beeps, which should not happen on a good MOSFET.

If the flex cable is still attached to the SoC, it should read something like 0.20 or even 0.40 iirc, on one side and almost near (or at) 0 on the other side of the capacitor. That side is ground.

iirc in the inner pads (SP1 and SP2) are connected to the MOSFETs and the outer ones are just ground...?

Hacking Need help with Picofly Switch Lite (==* CPU always reach BCT) - What could be wrong ?

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