diff --git a/src/deh_soc.c b/src/deh_soc.c
index d63301901..87cc55328 100644
--- a/src/deh_soc.c
+++ b/src/deh_soc.c
@@ -1183,8 +1183,10 @@ void readlevelheader(MYFILE *f, char * name)
 				mapheaderinfo[num]->numlaps = (UINT8)i;
 			else if (fastcmp(word, "UNLOCKABLE"))
 			{
-				if (i >= 0 && i <= MAXUNLOCKABLES) // 0 for no unlock required, anything else requires something
-					mapheaderinfo[num]->unlockrequired = (SINT8)i - 1;
+				if (i == 0 || word2[0] == 'F' || word2[0] == 'N')
+					mapheaderinfo[num]->unlockrequired = MAXUNLOCKABLES;
+				else if (i > 0 && i <= MAXUNLOCKABLES) // 0 for no unlock required, anything else requires something
+					mapheaderinfo[num]->unlockrequired = (UINT8)(i-1);
 				else
 					deh_warning("Level header %d: invalid unlockable number %d", num, i);
 			}
@@ -3087,8 +3089,10 @@ void readcupheader(MYFILE *f, cupheader_t *cup)
 			}
 			else if (fastcmp(word, "UNLOCKABLE"))
 			{
-				if (i >= 0 && i <= MAXUNLOCKABLES) // 0 for no unlock required, anything else requires something
-					cup->unlockrequired = (SINT8)i - 1;
+				if (i == 0 || word2[0] == 'F' || word2[0] == 'N')
+					cup->unlockrequired = MAXUNLOCKABLES;
+				else if (i > 0 && i <= MAXUNLOCKABLES) // 0 for no unlock required, anything else requires something
+					cup->unlockrequired = (UINT8)(i-1);
 				else
 					deh_warning("%s Cup: invalid unlockable number %d", cup->name, i);
 			}
diff --git a/src/dehacked.c b/src/dehacked.c
index 005924ef4..b2fd16e03 100644
--- a/src/dehacked.c
+++ b/src/dehacked.c
@@ -486,7 +486,7 @@ static void DEH_LoadDehackedFile(MYFILE *f, boolean mainfile)
 					{
 						cup = Z_Calloc(sizeof (cupheader_t), PU_STATIC, NULL);
 						cup->id = numkartcupheaders;
-						cup->unlockrequired = -1;
+						cup->unlockrequired = MAXUNLOCKABLES;
 						deh_strlcpy(cup->name, word2,
 							sizeof(cup->name), va("Cup header %s: name", word2));
 						if (prev != NULL)
diff --git a/src/doomstat.h b/src/doomstat.h
index 55644bfb2..d7b09f060 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -355,7 +355,7 @@ typedef struct cupheader_s
 	UINT8 numlevels;						///< Number of levels defined in levellist
 	UINT8 numbonus;							///< Number of bonus stages defined
 	UINT8 emeraldnum;						///< ID of Emerald to use for special stage (1-7 for Chaos Emeralds, 8-14 for Super Emeralds, 0 for no emerald)
-	SINT8 unlockrequired;					///< An unlockable is required to select this cup. -1 for no unlocking required.
+	UINT8 unlockrequired;					///< An unlockable is required to select this cup. -1 for no unlocking required.
 	struct cupheader_s *next;				///< Next cup in linked list
 } cupheader_t;
 
@@ -391,7 +391,7 @@ typedef struct
 	// Selection metadata
 	char keywords[33];					///< Keywords separated by space to search for. 32 characters.
 
-	SINT8 unlockrequired;				///< Is an unlockable required to play this level? -1 if no.
+	UINT8 unlockrequired;				///< Is an unlockable required to play this level? -1 if no.
 	UINT8 levelselect;					///< Is this map available in the level select? If so, which map list is it available in?
 	UINT16 menuflags;					///< LF2_flags: options that affect record attack menus
 
diff --git a/src/g_game.c b/src/g_game.c
index bafbf2ec3..f00ffcbe5 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -3870,7 +3870,7 @@ static void G_GetNextMap(void)
 			while (cup)
 			{
 				// Not unlocked? Grab the next result afterwards
-				if (!marathonmode && cup->unlockrequired != -1 && !gamedata->unlocked[cup->unlockrequired])
+				if (!marathonmode && cup->unlockrequired < MAXUNLOCKABLES && !gamedata->unlocked[cup->unlockrequired])
 				{
 					cup = cup->next;
 					gettingresult = 1;
diff --git a/src/k_menudraw.c b/src/k_menudraw.c
index c72871577..a3cae5651 100644
--- a/src/k_menudraw.c
+++ b/src/k_menudraw.c
@@ -1911,7 +1911,7 @@ static void M_DrawCupPreview(INT16 y, cupheader_t *cup)
 
 	V_DrawFill(0, y, BASEVIDWIDTH, 54, 31);
 
-	if (cup && (cup->unlockrequired == -1 || gamedata->unlocked[cup->unlockrequired]))
+	if (cup && (cup->unlockrequired >= MAXUNLOCKABLES || gamedata->unlocked[cup->unlockrequired]))
 	{
 		i = (cupgrid.previewanim / 82) % cup->numlevels;
 		while (x < BASEVIDWIDTH + pad)
@@ -1949,7 +1949,7 @@ static void M_DrawCupTitle(INT16 y, cupheader_t *cup)
 
 	if (cup)
 	{
-		boolean unlocked = (cup->unlockrequired == -1 || gamedata->unlocked[cup->unlockrequired]);
+		boolean unlocked = (cup->unlockrequired >= MAXUNLOCKABLES || gamedata->unlocked[cup->unlockrequired]);
 		UINT8 *colormap = R_GetTranslationColormap(TC_RAINBOW, SKINCOLOR_GREY, GTC_MENUCACHE);
 		patch_t *icon = W_CachePatchName(cup->icon, PU_CACHE);
 		const char *str = (unlocked ? va("%s Cup", cup->name) : "???");
@@ -2017,7 +2017,7 @@ void M_DrawCupSelect(void)
 
 			V_DrawScaledPatch(x, y, 0, patch);
 
-			if (iconcup->unlockrequired != -1 && !gamedata->unlocked[iconcup->unlockrequired])
+			if (iconcup->unlockrequired < MAXUNLOCKABLES && !gamedata->unlocked[iconcup->unlockrequired])
 			{
 				patch_t *st = W_CachePatchName(va("ICONST0%d", (cupgrid.previewanim % 4) + 1), PU_CACHE);
 				V_DrawScaledPatch(x + 8, y + icony, 0, st);
diff --git a/src/k_menufunc.c b/src/k_menufunc.c
index 07af02502..b1c34c19f 100644
--- a/src/k_menufunc.c
+++ b/src/k_menufunc.c
@@ -3459,7 +3459,7 @@ static void M_LevelListFromGametype(INT16 gt)
 
 		while (cup)
 		{
-			if (cup->unlockrequired == -1 || gamedata->unlocked[cup->unlockrequired])
+			if (cup->unlockrequired >= MAXUNLOCKABLES || gamedata->unlocked[cup->unlockrequired])
 			{
 				highestid = cup->id;
 				if (Playing() && mapheaderinfo[gamemap-1] && mapheaderinfo[gamemap-1]->cup == cup)
@@ -3593,7 +3593,7 @@ void M_CupSelectHandler(INT32 choice)
 		M_SetMenuDelay(pid);
 
 		if ((!newcup)
-			|| (newcup && newcup->unlockrequired != -1 && !gamedata->unlocked[newcup->unlockrequired])
+			|| (newcup && newcup->unlockrequired < MAXUNLOCKABLES && !gamedata->unlocked[newcup->unlockrequired])
 			|| (newcup->cachedlevels[0] == NEXTMAP_INVALID))
 		{
 			S_StartSound(NULL, sfx_s3kb2);
diff --git a/src/m_cond.c b/src/m_cond.c
index 4bf644e23..46f81cfc8 100644
--- a/src/m_cond.c
+++ b/src/m_cond.c
@@ -761,11 +761,23 @@ UINT8 M_MapLocked(INT32 mapnum)
 	// That just makes hosts' lives hell.
 	if (dedicated)
 		return false;
+
+	// No skipping over any part of your marathon.
+	if (marathonmode)
+		return false;
 	
-	if (!mapheaderinfo[mapnum-1] || mapheaderinfo[mapnum-1]->unlockrequired < 0)
+	if (!mapheaderinfo[mapnum-1])
 		return false;
 
-	if (!gamedata->unlocked[mapheaderinfo[mapnum-1]->unlockrequired])
+	if (mapheaderinfo[mapnum-1]->cup)
+	{
+		if ((mapheaderinfo[mapnum-1]->cup->unlockrequired < MAXUNLOCKABLES)
+			&& (!gamedata->unlocked[mapheaderinfo[mapnum-1]->cup->unlockrequired]))
+			return true;
+	}
+
+	if ((mapheaderinfo[mapnum-1]->unlockrequired < MAXUNLOCKABLES)
+		&& (!gamedata->unlocked[mapheaderinfo[mapnum-1]->unlockrequired]))
 		return true;
 
 	return false;
diff --git a/src/p_setup.c b/src/p_setup.c
index 9c06e7038..3e9747505 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -400,7 +400,7 @@ static void P_ClearSingleMapHeaderInfo(INT16 num)
 	mapheaderinfo[num]->palette = UINT16_MAX;
 	mapheaderinfo[num]->encorepal = UINT16_MAX;
 	mapheaderinfo[num]->numlaps = NUMLAPS_DEFAULT;
-	mapheaderinfo[num]->unlockrequired = -1;
+	mapheaderinfo[num]->unlockrequired = MAXUNLOCKABLES;
 	mapheaderinfo[num]->levelselect = 0;
 	mapheaderinfo[num]->levelflags = 0;
 	mapheaderinfo[num]->menuflags = 0;