Hacking Hardware Picofly - a HWFLY switch modchip

[Viktorsilva]

Thank, do you recommend I do the wire or the blob for the sake of testing? I am waiting on my solder mask and microscope before I do anything

in this case, i would aplly solder mask on every ground contact and leave clk trace and via exposed. Then aplly some flux on it and low temperature melt solder paste (try to create a bulb to connect both). if it doesn´t work, cut a small piece of copper wire and use it has a bridge. Dont use a solder iron, it´s easier with a heat gun. Dont forget to put some kapton tape to prevent some solder ball to get under the CPU.

 

[MrScopi]

I'm getting the ==* mosfet error on my rear-soldered mosfet. Is there a way to further diagnose the error, such as low current or something? Or can I only just keep redoing and redoing the joints?

Thanks for any help!

Spoiler: pic of mosfet

 

[_kedo_]

I'm getting the ==* mosfet error on my rear-soldered mosfet. Is there a way to further diagnose the error, such as low current or something? Or can I only just keep redoing and redoing the joints?

Thanks for any help!

Spoiler: pic of mosfet

View attachment 419823

Put your mosfet closer to capacitor and use thicker wires for source and drain

 

[MrScopi]

Put your mosfet closer to capacitor and use thicker wires for source and drain

I'll try that once this 30 awg (instead of 40 awg) arrives. What's the advantage or reasoning behind that? I see it posted but I don't understand what the mosfet is doing that requires certain thicknesses. Presumably to have the lowest possible resistance?

 

[DumbSolder]

in this case, i would aplly solder mask on every ground contact and leave clk trace and via exposed. Then aplly some flux on it and low temperature melt solder paste (try to create a bulb to connect both). if it doesn´t work, cut a small piece of copper wire and use it has a bridge. Dont use a solder iron, it´s easier with a heat gun. Dont forget to put some kapton tape to prevent some solder ball to get under the CPU.

it's fine too if I apply solder mask to the cpu area to prevent solder from getting in there?

 

[_kedo_]

I'll try that once this 30 awg (instead of 40 awg) arrives. What's the advantage or reasoning behind that? I see it posted but I don't understand what the mosfet is doing that requires certain thicknesses. Presumably to have the lowest possible resistance?

MOSFET shorts power rail of boot processor to cause a glitch. In pulse it handles 20-40A, so you need to use short and thick wires. 0.2 mm wire is good for this job.

 

[QuiTim]

I'll try that once this 30 awg (instead of 40 awg) arrives. What's the advantage or reasoning behind that? I see it posted but I don't understand what the mosfet is doing that requires certain thicknesses. Presumably to have the lowest possible resistance?

In your picture, the upper joint in the cap might be a cold joint since sometimes the enamel on the wire does not burn and the wire is just traped inside the solder joint while still insulated. The other points are not making good contact as well.
You should skip the wire and press the mosfet to the cap and solder directly.
See the pic (sorry for the quality).

 

[DumbSolder]

in this case, i would aplly solder mask on every ground contact and leave clk trace and via exposed. Then aplly some flux on it and low temperature melt solder paste (try to create a bulb to connect both). if it doesn´t work, cut a small piece of copper wire and use it has a bridge. Dont use a solder iron, it´s easier with a heat gun. Dont forget to put some kapton tape to prevent some solder ball to get under the CPU.

This is where I am at right now, I am going to do the low melt solder paste route with 36 awg wire

 

[Viktorsilva]

Congratulations, you did a good job preparing the motherboard for track recovery. Now it's time to wait for the next step to be executed with carefully in order to achieve success. Yes, you can put a small amount of solder mask to prevent anything from getting under the cpu. Pay attention to the thickness of the wire, the thinner the better.

 

[DumbSolder]

Congratulations, you did a good job preparing the motherboard for track recovery. Now it's time to wait for the next step to be executed with carefully in order to achieve success. Yes, you can put a small amount of solder mask to prevent anything from getting under the cpu. Pay attention to the thickness of the wire, the thinner the better.

it worked but it's a purple screen

 

[psycho-neon]

it worked but it's a purple screen

Try to reflow the 4.7k ohm resistor of cmd line. Sometime when the soldering iron is too hot, the pad beneath is separated. Otherwise try to replace it if you have.

 

[DumbSolder]

Try to reflow the 4.7k ohm resistor of cmd line. Sometime when the soldering iron is too hot, the pad beneath is separated. Otherwise try to replace it if you have.

Before I do that, it gets normal readings. Should I reflow it regardless?

 

[Viktorsilva]

Before I do that, it gets normal readings. Should I reflow it regardless?

The purple screen is a problem usually related to a failure of the 4.7K resistor at the point where the CMD is soldered. Normally it is resolved by replacing it. Can you post a image of it ?

 

[DumbSolder]

The purple screen is a problem usually related to a failure of the 4.7K resistor at the point where the CMD is soldered. Normally it is resolved by replacing it. Can you post a image of it ?

it flew away to the 9th dimension, im trying to look for replacements.

 

[GelmerB]

I am getting blue flashing light on pico and eventually glitches but takes a while. I used 2x 47ohm resistor on cmd and dat0.

any suggestions?

 

[abal1000x]

I am getting blue flashing light on pico and eventually glitches but takes a while. I used 2x 47ohm resistor on cmd and dat0.

any suggestions?

Seems like dat0 flex adapter common problem on oled.

 

[GelmerB]

Seems like dat0 flex adapter common problem on oled.

Its a v2, does that change anything?

 

[psycho-neon]

Its a v2, does that change anything?

Check the cmd line or the cpu flex line. Make sure they are solid connections.

Some emmc such as Toshiba tends to have long glitching time from my experience (takes between 60seconds max) double check that also if you have toshiba emmc.

 

[Viktorsilva]

Its a v2, does that change anything?

Did you used flex on CPU ? wires on the other points ? Post some pictures please. I allways get instant boot on every v1 & V2 (Picofly, HWfly, Seed Xiao)

Post automatically merged: Feb 15, 2024

it flew away to the 9th dimension, im trying to look for replacements.

thats why you are having a purple screen. You really need to improve your solders skills if you pretend to go on with this kind of project.

 

[DumbSolder]

Did you used flex on CPU ? wires on the other points ? Post some pictures please. I allways get instant boot on every v1 & V2 (Picofly, HWfly, Seed Xiao)

Post automatically merged: Feb 15, 2024

thats why you are having a purple screen. You really need to improve your solders squils if you pretend to go on with this kind of project.

Yeah I should've covered the surrounding area to prevent killing it in the first place but yeah it flew away when I grabbed it with my tweezers. I ordered 0201 4.7k resistors.

Also should I buy capacitors just in case? or is the blown resistor the only reason for the purple screen? I think I read a busted emmc chip can cause a purple screen and if that were the case then I could always boot to hakete and install and boot to linux or windows right?