ok fine (this still doesn't work!)

core/src/fos/FOSTypeIO.java

@@ -1,8 +1,28 @@
 package fos;
 
+import arc.util.io.Reads;
 import mindustry.annotations.Annotations;
+import mindustry.entities.units.WeaponMount;
 import mindustry.io.TypeIO;
 
 @Annotations.TypeIOHandler
 public class FOSTypeIO extends TypeIO {
+    public static WeaponMount[] readMounts(Reads read) {
+        WeaponMount[] mounts = new WeaponMount[read.b()];
+
+        for(int i = 0; i < mounts.length; i++){
+            byte state = read.b();
+            float ax = read.f(), ay = read.f();
+
+            if(i <= mounts.length - 1){
+                WeaponMount m = mounts[i];
+                m.aimX = ax;
+                m.aimY = ay;
+                m.shoot = (state & 1) != 0;
+                m.rotate = (state & 2) != 0;
+            }
+        }
+
+        return mounts;
+    }
 }

core/src/fos/type/units/comp/LumoniPlayerUnitComp.java

@@ -1,15 +1,28 @@
 package fos.type.units.comp;
 
+import arc.util.io.*;
+import fos.FOSTypeIO;
 import mindustry.annotations.Annotations;
 import mindustry.entities.units.WeaponMount;
 import mindustry.gen.*;
+import mindustry.io.TypeIO;
 
 // FIXME mounts
 @Annotations.Component
 public abstract class LumoniPlayerUnitComp implements Weaponsc, Entityc, Syncc {
     @Annotations.Import WeaponMount[] mounts;
-    WeaponMount[] syncMounts;
 
+    @Override
+    public void write(Writes write) {
+        TypeIO.writeMounts(write, mounts);
+    }
+
+    @Override
+    public void read(Reads read) {
+        mounts = FOSTypeIO.readMounts(read);
+    }
+
+/*
     @Override
     public void afterRead() {
         mounts = syncMounts;
@@ -19,4 +32,5 @@ public void afterRead() {
     public void afterSync() {
         mounts = syncMounts;
     }
+*/
 }