diff --git a/docs/software/mesh-alg.md b/docs/software/mesh-alg.md
index 7d7837be..ecad282a 100644
--- a/docs/software/mesh-alg.md
+++ b/docs/software/mesh-alg.md
@@ -31,6 +31,9 @@ dsr tasks
 optimizations / low priority:
 
 - read @cyclomies long email with good ideas on optimizations and reply
+- Remove NodeNum assignment algorithm (now that we use 4 byte node nums)
+- make android app warn if firmware is too old or too new to talk to
+- change nodenums and packetids in protobuf to be fixed32
 - low priority: think more careful about reliable retransmit intervals
 - make ReliableRouter.pending threadsafe
 - bump up PacketPool size for all the new ack/nak/routing packets
diff --git a/src/mesh/MeshTypes.h b/src/mesh/MeshTypes.h
index f491ce50..adba7841 100644
--- a/src/mesh/MeshTypes.h
+++ b/src/mesh/MeshTypes.h
@@ -9,7 +9,7 @@
 typedef uint8_t NodeNum;
 typedef uint8_t PacketId; // A packet sequence number
 
-#define NODENUM_BROADCAST 255
+#define NODENUM_BROADCAST (sizeof(NodeNum) == 4 ? UINT32_MAX : UINT8_MAX)
 #define ERRNO_OK 0
 #define ERRNO_NO_INTERFACES 33
 #define ERRNO_UNKNOWN 32 // pick something that doesn't conflict with RH_ROUTER_ERROR_UNABLE_TO_DELIVER
diff --git a/src/mesh/NodeDB.cpp b/src/mesh/NodeDB.cpp
index faa03593..1e263134 100644
--- a/src/mesh/NodeDB.cpp
+++ b/src/mesh/NodeDB.cpp
@@ -178,8 +178,10 @@ void NodeDB::init()
  */
 void NodeDB::pickNewNodeNum()
 {
-    // FIXME not the right way to guess node numes
-    uint8_t r = ourMacAddr[5];
+    // Pick an initial nodenum based on the macaddr
+    NodeNum r = sizeof(NodeNum) == 1 ? ourMacAddr[5]
+                                     : ((ourMacAddr[2] << 24) | (ourMacAddr[3] << 16) | (ourMacAddr[4] << 8) | ourMacAddr[5]);
+
     if (r == 0xff || r < NUM_RESERVED)
         r = NUM_RESERVED; // don't pick a reserved node number
 
diff --git a/src/mesh/RadioInterface.cpp b/src/mesh/RadioInterface.cpp
index 45ecc42a..c7edf74d 100644
--- a/src/mesh/RadioInterface.cpp
+++ b/src/mesh/RadioInterface.cpp
@@ -26,7 +26,7 @@ separated by 2.16 MHz with respect to the adjacent channels. Channel zero starts
 
 RadioInterface::RadioInterface() : txQueue(MAX_TX_QUEUE)
 {
-    assert(sizeof(PacketHeader) == 4); // make sure the compiler did what we expected
+    assert(sizeof(PacketHeader) == 4 || sizeof(PacketHeader) == 16); // make sure the compiler did what we expected
 
     myNodeInfo.num_channels = NUM_CHANNELS;
 
diff --git a/src/mesh/RadioInterface.h b/src/mesh/RadioInterface.h
index 41976375..64222a76 100644
--- a/src/mesh/RadioInterface.h
+++ b/src/mesh/RadioInterface.h
@@ -19,7 +19,9 @@
  * wtih the old radiohead implementation.
  */
 typedef struct {
-    uint8_t to, from, id;
+    NodeNum to, from; // can be 1 byte or four bytes
+
+    PacketId id; // can be 1 byte or 4 bytes
 
     /**
      * Usage of flags:
diff --git a/src/mesh/Router.cpp b/src/mesh/Router.cpp
index dc7409a0..eb8a1ab3 100644
--- a/src/mesh/Router.cpp
+++ b/src/mesh/Router.cpp
@@ -51,7 +51,8 @@ PacketId generatePacketId()
     static uint32_t i; // Note: trying to keep this in noinit didn't help for working across reboots
     static bool didInit = false;
 
-    uint32_t numPacketId = 255; // 0 is consider invalid
+    assert(sizeof(PacketId) == 4 || sizeof(PacketId) == 1);                // only supported values
+    uint32_t numPacketId = sizeof(PacketId) == 1 ? UINT8_MAX : UINT32_MAX; // 0 is consider invalid
 
     if (!didInit) {
         didInit = true;
@@ -60,7 +61,7 @@ PacketId generatePacketId()
     }
 
     i++;
-    PacketId id = (i % numPacketId) + 1; // return number between 1 and 255 (ie - never zero)
+    PacketId id = (i % numPacketId) + 1; // return number between 1 and numPacketId (ie - never zero)
     myNodeInfo.current_packet_id = id;   // Kinda crufty - we keep updating this so the phone can see a current value
     return id;
 }