How to replace raspberry pi os with dietpi?

Hello,
It’s been a while since I have had the time to play with my Raspberry Pis. My Pi 4 is running smoothly with DietPi and I managed to boot up my Pi5 with is flashed with Raspberry Pi OS. Nothing wrong with it, really, I just prefer DietPi.

From with Raspberry Pi OS I opened up a console and did:

$ sudo rpi-eeprom-config --edit

with reads:

[all]
BOOT_UART=1
POWER_OFF_ON_HALT=0
BOOT_ORDER=0xf461

I understand the boot order above is declared as USB > NVME > SD.

I can’t access the sd card slot on the case I am using.

I have the latest dietpi image for the pi5 and flashed it via belena.

But the pi will not detect the usb during boot.

How can I get this working?

Cheers,

You are using a pen stick or USB HDD?