Fast boot is not a single kernel option. It is the result of measuring and shortening every stage between power-on and useful work.

This is an English DEV.to draft based on a Silicon LogiX technical article. The canonical source is linked at the end.

Why it matters

For HMIs, gateways and control devices, boot time affects perceived quality and sometimes functional requirements.

A desktop-like boot path is rarely acceptable in a dedicated embedded product.

Architecture notes

The chain includes ROM, bootloader, kernel decompression, driver initialization, root filesystem mount and init services.

U-Boot delays, unused kernel drivers and broad systemd dependencies are common sources of avoidable latency.

Filesystem choice matters: SquashFS, initramfs, ext4 and read-only layouts have different trade-offs.

The product should define the moment it is useful, not only the moment Linux finishes booting.

Practical checklist

[ ] Instrument boot with timestamps before optimizing.

[ ] Remove bootloader…