diff --git a/constants/serial_constants.asm b/constants/serial_constants.asm
index 390390cc2..0b711e877 100644
--- a/constants/serial_constants.asm
+++ b/constants/serial_constants.asm
@@ -28,3 +28,5 @@ SERIAL_PREAMBLE_BYTE              EQU $fd
 SERIAL_NO_DATA_BYTE               EQU $fe
 ; signals the end of one part of a patch list (there are two parts) for player/enemy party data
 SERIAL_PATCH_LIST_PART_TERMINATOR EQU $ff
+
+SERIAL_PREAMBLE_LENGTH EQU 6
diff --git a/engine/link/link.asm b/engine/link/link.asm
index 4f794eb00..d42fb6818 100644
--- a/engine/link/link.asm
+++ b/engine/link/link.asm
@@ -632,7 +632,7 @@ FixDataForLinkTransfer:
 Link_PrepPartyData_Gen1:
 	ld de, wLinkData
 	ld a, SERIAL_PREAMBLE_BYTE
-	ld b, PARTY_LENGTH
+	ld b, SERIAL_PREAMBLE_LENGTH
 .loop1
 	ld [de], a
 	inc de
@@ -798,7 +798,7 @@ Link_PrepPartyData_Gen1:
 Link_PrepPartyData_Gen2:
 	ld de, wLinkData
 	ld a, SERIAL_PREAMBLE_BYTE
-	ld b, PARTY_LENGTH
+	ld b, SERIAL_PREAMBLE_LENGTH
 .loop1
 	ld [de], a
 	inc de