How to update firmware on Pi 4

Hi, have been running 6.26 on a Pi 4 board and the splash screen says it’s running hot…I read that there’s a new firmware package that reduces heat and I’m trying to update to that new firmware. How do I do that on DietPi? I vaguely recall seeing an option in Dietpi-config in the past, but I don’t see that now. I have another Pi 4 running debian, and the command to update is rpi-update, but that does not work here. Also, after some googling, I also tried apt-get dist-upgrade, but that did not yield any updates. Does that mean my Pi 4 already has the latest firmware? Thank you!

On RPi generally apt update && apt upgrade can be used to update the firmware. However on RPi4 there is another firmware part (bootloader and some USB driver) stored on an internal EEPROM. We added support to update it with v6.27 which is aimed to be released soon. However you can test it:

G_AGI rpi-eeprom rpi-eeprom-images flashrom libraspberrypi-bin raspberrypi-bootloader
# - Workaround:
# Update/flash new bootloader and VL805 USB firmware to EEPROM
rpi-eeprom-update -a
# Required? Enable update service to run on every boot
systemctl enable rpi-eeprom-update