RPi-B shutting down during boot

I have a Raspberry Pi (1) model B,

Installed latest DietPi ( updated 15.12.2025 ) on a 1 GB SD card. I watched the boot sequence via HDMI output. Just before the login prompt it says systemd power-off and then shut downs.

Though, the real problem is I believe, it says FAILED for kernel.command-line service. That’s where it goes downhill from there.

What may be the reason for this?