Flashing WendyOS

The wendy os install command writes a WendyOS image to a drive (SD card, USB, NVMe enclosure, etc.).

Usage

wendy os install --device-type <type> --drive <device>

Use wendy os list-drives to enumerate available drives.

How it works

wendy os install downloads the WendyOS release zip (~5.5 GB) for the selected device type and writes it directly to the target drive. The compressed zip is never fully extracted to disk — the image entry is streamed from the zip to the drive in a single pass, so the peak temporary disk usage is the zip file itself.

Caching

The downloaded zip is cached locally. On subsequent installs for the same device type the cached zip is used directly, avoiding a repeat download. Legacy .img cache entries from older versions of the tool are still recognised as a fallback.

Use wendy os download to pre-populate the cache without performing an install.

Progress

While writing, the tool reports bytes written to the drive. There is no separate "Extracting image…" step.

Disk usage

Platform notes

macOS

The image is written via dd to the raw disk device (/dev/rdiskN), bypassing the filesystem buffer cache. NVMe drives in USB enclosures use a 64 MiB block size to reduce per-write overhead over the USB link.

Linux

Before writing, all mounted partitions on the target disk are unmounted automatically. lsblk is used to enumerate every partition (including nested ones), and each mounted partition is unmounted by its mountpoint using sudo umount. Partitions with deeper mountpoints are unmounted before shallower ones to avoid EBUSY errors. If any partition cannot be unmounted, the error is reported and the write does not proceed.

The image is written via dd with conv=fdatasync to ensure the device is flushed before the command exits. NVMe drives use a 64 MiB block size and oflag=direct to bypass the page cache.

Windows

The image is written directly to the raw disk device. After writing, any auto-assigned drive letters are removed from all partitions to prevent phantom drives from appearing in Explorer. For fixed (non-removable) disks, the disk is then taken offline. For removable media (USB, SD, MMC), the offline step is skipped — Windows does not support setting removable media offline, and physically removing the media serves as the eject action.