diff --git a/firmware/src/main.cpp b/firmware/src/main.cpp
index cc6e935..fc5f083 100644
--- a/firmware/src/main.cpp
+++ b/firmware/src/main.cpp
@@ -499,8 +499,14 @@ static void sendReticulumAnnounce() {
   uint8_t sig[64];
   ed25519_sign(sig, signed_data, sl, rnsEdPub, rnsEdPrv);
 
-  uint8_t pkt[2 + 16 + 1 + 64 + 10 + 10 + 64 + 32]; size_t p = 0;
-  pkt[p++] = 0x01;                             // flags: HEADER_1|BROADCAST|SINGLE|ANNOUNCE
+  uint8_t pkt[1 + 2 + 16 + 1 + 64 + 10 + 10 + 64 + 32]; size_t p = 0;
+  // RNode on-air framing: every LoRa frame starts with a 1-byte RNode header
+  // (RNode_Firmware transmit(): `random(256) & 0xF0`, split-flag clear for a
+  // single packet). RNode RX reads+strips it before handing the packet to RNS,
+  // so we must prepend it or the real RNS packet arrives shifted and fails to
+  // validate. Low nibble 0 = not a split packet.
+  pkt[p++] = 0x00;                             // RNode header (single, non-split)
+  pkt[p++] = 0x01;                             // RNS flags: HEADER_1|BROADCAST|SINGLE|ANNOUNCE
   pkt[p++] = 0x00;                             // hops
   memcpy(pkt + p, rnsDestHash, 16); p += 16;
   pkt[p++] = 0x00;                             // context = NONE