What is the difference between sysupgrade.tar and factory.img when installing the LEDE Project?

Question

Trying to download a firmware from my Netgear, I see options from

• R7800-squashfs-sysupgrade.tar
• R7800-squashfs-factory.img

What is the difference between the sysupgrade.tar and factory.img?

Answer 1

From this forum post by the moderator DoesItMatter,

sysupgrade.bin is for any router that is currently running either openwrt or gargoyle and can be flashed via the GUI.

factory.bin files are meant to be flashed over factory stock firmware routers - they usually have some extra "magic bytes" i.e. a trick header - to fool the factory firmware into thinking its reading its own factory firmware, not 3rd party firmware.

The docs affirm this,

• If your device is running the firmware it came with (often called “stock”, “factory”, or “vendor” firmware) download the file for a “factory installation” from Device Page or Device Tech data

• If your device is already running LEDE (or OpenWrt) download the file for a “sysupgrade installation” from Device Page or Device Techdata