cmd/earlyinit: remount root and set firmware path

The default search paths cannot be configured, configuring them here is most sound for now.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/earlyinit/main.go

@@ -94,6 +94,22 @@ func main() {
 		"",
 	))
 
+	// after top level has been set up
+	mustSyscall("remount root", Mount(
+		"",
+		"/",
+		"",
+		MS_REMOUNT|MS_BIND|
+			MS_RDONLY|MS_NODEV|MS_NOSUID|MS_NOEXEC,
+		"",
+	))
+
+	must(os.WriteFile(
+		"/sys/module/firmware_class/parameters/path",
+		[]byte("/system/lib/firmware"),
+		0,
+	))
+
 }
 
 // mustSyscall calls [log.Fatalln] if err is non-nil.