1) dl.sta.li is not on my site, and probably not on yours.
2) That's still suboptimal. You're giving each host on your LAN the ability to interfere with any newly-provisioned server. This is a perfect and hard-to-detect way for an attacker to pivot from "RCE on some random webapp" to "advanced persistent threat".
> This is a problem with all of the suckless software and it, well, sucks.
If you serve things over HTTP its easier to daisy-chain it in a PXE -> iPXE kind of setup. HTTPS is not supported by most boot-ROMs.
Keep your boot-image server on site and local and HTTP isn't a real world issue.