JustVik

Maybe this. Most smartphones have a modem inside, this modem has a separate closed-sourced operating system and it usually has the main priority in controlling the smartphone relative to the processor running the main operating system, such as Android. Sometimes the modem has access to the microphone or memory, even bypassing the CPU. Although maybe everyone already knows that.

VBUS, VSYS, 3V3 - it is all power pins.

As I understand by reading in the datasheet there are 3 ways to power the Pico board:

-USB Micro-B port

-VBUS Pin

-VSYS Pin

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VBUS - can be used for output

VSYS - can be used for output

3v3 - output power 3.3v

GND - ground

From datsasheet:

"VBUS is the micro-USB input voltage, connected to micro-USB port pin 1. This is nominally 5V (or 0V if the USB is not connected or not powered). VSYS is the main system input voltage, which can vary in the allowed range 1.8V to 5.5V, and is used by the on-board SMPS to generate the 3.3V for the RP2040 and its GPIO. 3V3_EN connects to the on-board SMPS enable pin, and is pulled high (to VSYS) via a 100kΩ resistor. To disable the 3.3V (which also de-powers the RP2040), short this pin low. 3V3 is the main 3.3V supply to RP2040 and its I/O, generated by the on-board SMPS. This pin can be used to power external circuitry (maximum output current will depend on RP2040 load and VSYS voltage, it is recommended to keep the load on this pin less than 300mA)

ADC_VREF is the ADC power supply (and reference) voltage, and is generated on Pico by filtering the 3.3V supply. This pin can be used with an external reference if better ADC performance is required. AGND is the ground reference for GPIO26-29, there is a separate analog ground plane running under these signals and terminating at this pin. If the ADC is not used or ADC performance is not critical, this pin can be connected to digital ground. RUN is the RP2040 enable pin, and has an internal (on-chip) pull-up resistor to 3.3V of about ~50kΩ. To reset RP2040, short this pin low."

But I’m not proffessional with microcontrollers.

Pass or qtpass if you need gui. Simple and efficient.

Sometimes I want to read the sources of the programs I use and learn how they work.

It’s not their fault that they can’t make Graphene OS for more models. It’s the fault of the manufacturers of these smartphones who always put a stick in the wheel for anyone who wants to make a privacy oriented OS for their smartphone models.