diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 7996f0af3..7bb646608 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,3 +1,6 @@
+August 19, 2008 (Changes by Graf Zahl)
+- Added Gez's patch for removing MF4_FIRERESIST.
+
 August 18, 2008 (SBARINFO patch)
 - Fixed: DrawBar would not show.
 - Fixed: IsSelected took string constants instead of identifiers.
diff --git a/src/actor.h b/src/actor.h
index f28ff7b16..b6c0eb02d 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -265,7 +265,6 @@ enum
 	MF4_LOOKALLAROUND	= 0x00010000,	// Monster has eyes in the back of its head
 	MF4_STANDSTILL		= 0x00020000,	// Monster should not chase targets unless attacked?
 	MF4_SPECTRAL		= 0x00040000,
-	MF4_FIRERESIST		= 0x00080000,	// Actor takes half damage from fire
 	MF4_NOSPLASHALERT	= 0x00100000,	// Splashes don't alert this monster
 	MF4_SYNCHRONIZED	= 0x00200000,	// For actors spawned at load-time only: Do not randomize tics
 	MF4_NOTARGETSWITCH	= 0x00400000,	// monster never switches target until current one is dead
diff --git a/src/p_interaction.cpp b/src/p_interaction.cpp
index 02d224cec..14dddb6d6 100644
--- a/src/p_interaction.cpp
+++ b/src/p_interaction.cpp
@@ -951,23 +951,14 @@ void P_DamageMobj (AActor *target, AActor *inflictor, AActor *source, int damage
 		if (olddam != damage && damage <= 0) return;
 	}
 
-	// to be removed and replaced by an actual damage factor 
-	// once the actors using it are converted to DECORATE.
-	if (mod == NAME_Fire && target->flags4 & MF4_FIRERESIST)
+	DmgFactors * df = target->GetClass()->ActorInfo->DamageFactors;
+	if (df != NULL)
 	{
-		damage /= 2;
-	}
-	else
-	{
-		DmgFactors * df = target->GetClass()->ActorInfo->DamageFactors;
-		if (df != NULL)
+		fixed_t * pdf = df->CheckKey(mod);
+		if (pdf != NULL)
 		{
-			fixed_t * pdf = df->CheckKey(mod);
-			if (pdf != NULL)
-			{
-				damage = FixedMul(damage, *pdf);
-				if (damage <= 0) return;
-			}
+			damage = FixedMul(damage, *pdf);
+			if (damage <= 0) return;
 		}
 	}
 
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index de2d358f5..d60bad331 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -100,6 +100,7 @@ enum
 	DEPF_SHORTMISSILERANGE,
 	DEPF_PICKUPFLASH,
 	DEPF_QUARTERGRAVITY,
+	DEPF_FIRERESIST,
 };
 
 static flagdef ActorFlags[]=
@@ -208,7 +209,6 @@ static flagdef ActorFlags[]=
 	DEFINE_FLAG(MF4, LOOKALLAROUND, AActor, flags4),
 	DEFINE_FLAG(MF4, STANDSTILL, AActor, flags4),
 	DEFINE_FLAG(MF4, SPECTRAL, AActor, flags4),
-	DEFINE_FLAG(MF4, FIRERESIST, AActor, flags4),
 	DEFINE_FLAG(MF4, NOSPLASHALERT, AActor, flags4),
 	DEFINE_FLAG(MF4, SYNCHRONIZED, AActor, flags4),
 	DEFINE_FLAG(MF4, NOTARGETSWITCH, AActor, flags4),
@@ -264,6 +264,7 @@ static flagdef ActorFlags[]=
 	DEFINE_DEPRECATED_FLAG(SHORTMISSILERANGE),
 	DEFINE_DEPRECATED_FLAG(LONGMELEERANGE),
 	DEFINE_DEPRECATED_FLAG(QUARTERGRAVITY),
+	DEFINE_DEPRECATED_FLAG(FIRERESIST),
 	DEFINE_DUMMY_FLAG(NONETID),
 	DEFINE_DUMMY_FLAG(ALLOWCLIENTSPAWN),
 };
@@ -434,6 +435,9 @@ static void HandleDeprecatedFlags(AActor *defaults, bool set, int index)
 	case DEPF_QUARTERGRAVITY:
 		defaults->gravity = set? FRACUNIT/4 : FRACUNIT;
 		break;
+	case DEPF_FIRERESIST:
+		if (set) defaults->GetClass()->ActorInfo->DamageFactors->Insert("Fire", 0.5);
+		else defaults->GetClass()->ActorInfo->DamageFactors->Remove("Fire");
 	case DEPF_PICKUPFLASH:
 		if (set)
 		{
diff --git a/wadsrc/static/actors/strife/loremaster.txt b/wadsrc/static/actors/strife/loremaster.txt
index f8e760eb9..39ffcea4c 100644
--- a/wadsrc/static/actors/strife/loremaster.txt
+++ b/wadsrc/static/actors/strife/loremaster.txt
@@ -19,8 +19,8 @@ ACTOR Loremaster 12
 	+NOBLOCKMONST
 	+INCOMBAT
 	+LOOKALLAROUND
-	+FIRERESIST
 	+NOICEDEATH
+	DamageFactor "Fire", 0.5
 	MinMissileChance 150
 	Tag "PRIEST"
 	SeeSound "loremaster/sight"
diff --git a/wadsrc/static/actors/strife/macil.txt b/wadsrc/static/actors/strife/macil.txt
index 0c11f0164..fbd52ecad 100644
--- a/wadsrc/static/actors/strife/macil.txt
+++ b/wadsrc/static/actors/strife/macil.txt
@@ -13,10 +13,10 @@ ACTOR Macil1 64 native
 	Monster
 	-COUNTKILL
 	+NOTDMATCH
-	+FIRERESIST
 	+NOICEDEATH
 	+NOSPLASHALERT
 	+NODAMAGE
+	DamageFactor "Fire", 0.5
 	MinMissileChance 150
 	SeeSound "macil/sight"
 	PainSound "macil/pain"
diff --git a/wadsrc/static/actors/strife/oracle.txt b/wadsrc/static/actors/strife/oracle.txt
index 347088638..6c0639a96 100644
--- a/wadsrc/static/actors/strife/oracle.txt
+++ b/wadsrc/static/actors/strife/oracle.txt
@@ -10,7 +10,7 @@ ACTOR Oracle 199 native
 	Height 56
 	Monster
 	+NOTDMATCH
-	+FIRERESIST
+	DamageFactor "Fire", 0.5
 	MaxDropoffHeight 32
 	Tag "Oracle"
 	DropItem "Meat"
@@ -31,4 +31,4 @@ ACTOR Oracle 199 native
 		ORCL Q -1
 		Stop
 	}
-}
\ No newline at end of file
+}
diff --git a/wadsrc/static/actors/strife/programmer.txt b/wadsrc/static/actors/strife/programmer.txt
index 41fdedff2..fef811b7e 100644
--- a/wadsrc/static/actors/strife/programmer.txt
+++ b/wadsrc/static/actors/strife/programmer.txt
@@ -21,9 +21,9 @@ ACTOR Programmer 71
 	+DONTMORPH
 	+NOBLOCKMONST
 	+LOOKALLAROUND
-	+FIRERESIST
 	+NOICEDEATH
 	+NOTARGETSWITCH
+	DamageFactor "Fire", 0.5
 	MinMissileChance 150
 	AttackSound "programmer/attack"
 	PainSound "programmer/pain"
diff --git a/wadsrc/static/actors/strife/strifebishop.txt b/wadsrc/static/actors/strife/strifebishop.txt
index 427483864..303129271 100644
--- a/wadsrc/static/actors/strife/strifebishop.txt
+++ b/wadsrc/static/actors/strife/strifebishop.txt
@@ -16,8 +16,8 @@ ACTOR StrifeBishop 187
 	+NOTDMATCH
 	+FLOORCLIP
 	+INCOMBAT
-	+FIRERESIST
 	+NOICEDEATH
+	DamageFactor "Fire", 0.5
 	MinMissileChance 150
 	MaxDropoffHeight 32
 	SeeSound "bishop/sight"