This article shows how to cross compile Linux kernel for Raspberry Pi 3 Model B, load the kernel and device tree from tftp server every time the board boots up.
nayab.xyz/rpi3b-elinux/embedde

Create partitions using fdisk tool for any SD card or USB drive. Build a file system in those partitions. In this tutorial we create two partitions, the first one with fat32 filesystem and the second one with ext4 filesystem.
nayab.xyz/linux-tools/partitio

Fosstodon

Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.