Switching off the Undervoltage Warning

The Raspberry Pi 5 is quite particular about power supplies. Many “powerful” mobile phone chargers deliver 25W or more, but often at higher voltages (9V, 12V) and not at the 5V/5A required by the Raspi, while weaker power supplies really do not provide sufficient power.

The message “This power supply is not capable to deliver 5A …” (or a small yellow lightning bolt icon in the upper right corner of the screen) appears on the Raspberry Pi 5 because it communicates with the power supply via the “USB-C Power Delivery (PD)” protocol. If the power supply doesn’t signal that it can deliver 5A at 5V, the Raspi reduces the current to the USB ports (from 1.6A to 600mA) as a safety precaution to prevent system crashes.

The command vcgencmd can be used to get some more insight into the current power consumption of you Raspi. With

vcgencmd get_throttled

you get information whether the Raspi is currently throttled due to low voltage. An output like

throttled=0x0

indicates that currently everything is alright.

vcgencmd pmic_read_adc

provides more detailed information.

If your problem is really only the incomplete communication between the Raspi and the power supply, here are three ways to get rid of the message:

## 1. The Clean Solution: The Official Power Supply Use the official Raspberry Pi 27W USB-C Power Supply. It’s one of the few that supports the exact 5V/5A profile. This will make the message disappear immediately, and all USB devices will receive full power.

## 2. The Configuration Solution (Ignore the Warning & Remove the USB Limit) If you know your power supply is stable and you don’t have any power-hungry USB devices (like external hard drives without their own power supply) connected, you can manually override the check.

### Method A: Via config.txt

Open the configuration file in the terminal: bash sudo joe /boot/firmware/config.txt (For older versions: /boot/config.txt)
Add this line to the end of the file: text usb_max_current_enable=1
Save and exit with Ctrl+KX.
Restart the Raspi.

### Method B: Via EEPROM Configuration (Recommended) This is the most reliable method to suppress the boot warning directly at the hardware level:

Enter the following command:
```
sudo rpi-eeprom-config --edit
```
Find or add the line PSU_MAX_CURRENT:
```
PSU_MAX_CURRENT=5000
```
Save with Ctrl+O, Enter, and exit with Ctrl+X.
Reboot the Raspi.

The Raspi will now “think” it has a 5A power supply.

## 3. What happens if you only suppress the message?

If you choose the software solution but your power supply is actually weak, the following can happen:

System crashes: As soon as you plug in a USB device, the voltage drops and the Pi restarts.
Undervoltage Warnings: The small yellow lightning bolt icon (or a warning in the upper right corner) will continue to appear if the voltage drops below 4.63V.

Important for CM5 users: Here the behaviour depends heavily on the carrier board. Some boards have their own current regulation, which tricks the module into thinking there’s enough power, while others pass the CM5 warning directly through.