Colin Percival 讓 FreeBSD 能夠支援 Firecrack：「Announcing the FreeBSD/Firecracker platform」，成為 Linux、OSv 以外的第三個支援的作業系統。對應的 patch 在「amd64: Add FIRECRACKER kernel configuration」這邊可以看到。
接下來是反過來，要送一些 patch 進去 Firecracker，讓他支援 FreeBSD：
Now that FreeBSD supported Firecracker, there was one more thing to do: Make Firecracker support FreeBSD.
看起來是基於之前在 2020 年的 patch (但當時沒被整進去) 再修改：
Alejandro Jimenez contributed patches two years ago, but they were never merged. Some of his code ended up in the linux-loader project (which Firecracker uses); but I spent a few weeks digging through his thousand lines of changes to figure out which went into linux-loader, which still applied cleanly to Firecracker, and which I had to rewrite from scratch — a task made more difficult by the fact that Firecracker is written in Rust, and I had never used Rust before! Nevertheless, I was eventually successful, and opened a PR with updated patches which I hope to see merged into mainline Firecracker in the upcoming weeks.
看起來兩邊都有 patch 要做才能支援，目前看起來 Firecracker 這邊沒動作了，大概是沒什麼動力...