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

Merihel · Wednesday at 11:32 PM

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...?

Merihel · 2026-06-26T15:23:16+0100

Thank you I'll try in continuity to see if those are dead.

I see sometimes values around 0.14, sometimes 0.10. On SP1 it's on the left side (0.01 on the right) and the other way around for sp2. Could it be that the capacitors are good but not connected to the board anymore? I read somewhere that one of the capacitors can be missing, it should still glitch (not sure about that info though).

You mean the 2 big pads on the bottom of the flex, on my first photo? Those are connected to ground yes.

master801 · 2026-06-26T16:46:34+0100

Merihel said:
Thank you I'll try in continuity to see if those are dead.

I see sometimes values around 0.14, sometimes 0.10. On SP1 it's on the left side (0.01 on the right) and the other way around for sp2. Could it be that the capacitors are good but not connected to the board anymore? I read somewhere that one of the capacitors can be missing, it should still glitch (not sure about that info though).

You mean the 2 big pads on the bottom of the flex, on my first photo? Those are connected to ground yes.

You can still have a capacitor missing, it still work, and it still glitch, yes.

Those are bad values. You should be getting near 0 at the left side of the capacitor of SP1 (remember what I said about one side being ground?), and about 0.010 to 0.020 on the right side. Vice-versa for SP2. About 0.010 to 0.020 on the left side of SP2, then near 0 on the right side. In diode mode, with the negative probe on ground and positive probe probing values.

(I have my broken v2 with a Picofly install in front of me to reference It has a problem with the eMMC, not anything else.)

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

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