diff --git a/descriptions/rep/en_us.lua b/descriptions/rep/en_us.lua
index bea45f85..3a78369e 100644
--- a/descriptions/rep/en_us.lua
+++ b/descriptions/rep/en_us.lua
@@ -34,6 +34,7 @@ local repCollectibles={
 	[52] = {"52", "Dr. Fetus", "Bomb tears#Each bomb deals 10x your damage#If that results in over 60 damage, it instead deals 5x your damage + 30#↓ -60% Tears down"}, --Dr. Fetus
 	[53] = {"53", "Magneto", "Magnetic attraction for pickups#Opens chests remotely, ignoring damage of spike chests"}, -- Magneto
 	[55] = {"55", "Mom's Eye", "Chance to shoot a tear backwards"}, -- Mom's Eye
+	[59] = {"59", "The Book of Belial", "<Item not obtainable>"}, -- The Book of Belial (Judas's Birthright Version)
 	[62] = {"62", "Charm of the Vampire", "↑ +0.3 Damage up#Heals half a heart for every 13 enemies killed"}, -- Charm of the Vampire
 	[64] = {"64", "Steam Sale", "-50% on shop items price#Getting this item multiple times reduces the price further"}, -- Steam Sale
 	[67] = {"67", "Sister Maggy", "Normal tear familiar#Deals 6 damage per tear"}, -- Sister Maggy
diff --git a/eid_api.lua b/eid_api.lua
index 9dde15d3..19259b12 100644
--- a/eid_api.lua
+++ b/eid_api.lua
@@ -436,6 +436,7 @@ function EID:getObjectName(Type, Variant, SubType)
 		end
 	end
 	if tableName == "collectibles" then
+		if EID.itemConfig:GetCollectible(SubType) == nil then return Type.."."..Variant.."."..SubType end
 		local vanillaName = EID.itemConfig:GetCollectible(SubType).Name
 		return name or (not string.find(vanillaName, "^#") and vanillaName) or EID.descriptions["en_us"][tableName][SubType][2] or vanillaName
 	elseif tableName == "trinkets" then
@@ -766,8 +767,7 @@ function EID:getSpindownResult(collectibleID)
 end
 
 function EID:GetMaxCollectibleID()
-	--start a little lower than NUM_COLLECTIBLES, due to mods with outdated items.xmls that are missing newer items
-	local id = CollectibleType.NUM_COLLECTIBLES-17
+	local id = CollectibleType.NUM_COLLECTIBLES-1
 	local step = 16
 	while step > 0 do
 		if EID.itemConfig:GetCollectible(id+step) ~= nil then
@@ -805,6 +805,7 @@ function EID:isCollectibleUnlockedAnyPool(collectibleID)
 	--THIS FUNCTION IS FOR REPENTANCE ONLY due to using Repentance XML data; currently used by the Achievement Check, Spindown Dice, and Bag of Crafting
 	if not REPENTANCE then return true end
 	local item = EID.itemConfig:GetCollectible(collectibleID)
+	if item == nil then return false end
 	if EID.itemUnlockStates[collectibleID] == nil then
 		--whitelist all quest items and items with no associated achievement
 		if item.AchievementID == -1 or (item.Tags and item.Tags & ItemConfig.TAG_QUEST == ItemConfig.TAG_QUEST) then
diff --git a/eid_bagofcrafting.lua b/eid_bagofcrafting.lua
index f92de2ce..673d402a 100644
--- a/eid_bagofcrafting.lua
+++ b/eid_bagofcrafting.lua
@@ -184,16 +184,13 @@ for i = 1, EID.XMLMaxItemID do
 	end
 end
 
---don't sort if there's a collectible ID discrepancy
-if EID:GetMaxCollectibleID() == EID.XMLMaxItemID then
-	table.sort(sortedIDs, function(a, b)
-		if EID.XMLItemQualities[a] == EID.XMLItemQualities[b] then
-			return (EID:getObjectName(5, 100, a) < EID:getObjectName(5, 100, b))
-		else
-			return (EID.XMLItemQualities[a] > EID.XMLItemQualities[b])
-		end
-	end)
-end
+table.sort(sortedIDs, function(a, b)
+	if EID.XMLItemQualities[a] == EID.XMLItemQualities[b] then
+		return (EID:getObjectName(5, 100, a) < EID:getObjectName(5, 100, b))
+	else
+		return (EID.XMLItemQualities[a] > EID.XMLItemQualities[b])
+	end
+end)
 
 local customRNGSeed = 0x77777770
 local customRNGShift = {0,0,0}
@@ -603,6 +600,9 @@ local function detectModdedItems()
 	if maxItemID > EID.XMLMaxItemID then
 		return true
 	end
+	if EID.itemConfig:GetCollectible(EID.XMLMaxItemID) == nil then
+		return true
+	end
 	return false
 end
 
diff --git a/main.lua b/main.lua
index b6e6c490..b1d41231 100644
--- a/main.lua
+++ b/main.lua
@@ -551,27 +551,19 @@ EID:AddCallback(ModCallbacks.MC_POST_UPDATE, EID.onGameUpdate)
 local hasShownAchievementWarning = false
 
 local function renderAchievementInfo()
-	if REPENTANCE and not EID.Config.DisableAchievementCheck and game:GetFrameCount() < 10*30 then
-		if EID:GetMaxCollectibleID() < EID.XMLMaxItemID then
-			local demoDescObj = EID:getDescriptionObj(-999, -1, 1)
-			demoDescObj.Name = EID:getDescriptionEntry("AchievementWarningTitle") or ""
-			demoDescObj.Description = EID:getDescriptionEntry("OutdatedModWarningText") or ""
-			EID:displayPermanentText(demoDescObj)
-			hasShownAchievementWarning = true
-		else
-			local characterID = Game():GetPlayer(0):GetPlayerType()
-			--ID 21 = Tainted Isaac. Tainted characters have definitely beaten Mom! (Fixes Tainted Lost's item pools ruining this check)
-			if characterID < 21 and game.Challenge == 0 then
-				local hasBookOfRevelationsUnlocked = EID:isCollectibleUnlockedAnyPool(CollectibleType.COLLECTIBLE_BOOK_OF_REVELATIONS or CollectibleType.COLLECTIBLE_BOOK_REVELATIONS)
-				if not hasBookOfRevelationsUnlocked then
-					local hasCubeOfMeatUnlocked = EID:isCollectibleUnlockedAnyPool(CollectibleType.COLLECTIBLE_CUBE_OF_MEAT)
-					if not hasCubeOfMeatUnlocked then
-						local demoDescObj = EID:getDescriptionObj(-999, -1, 1)
-						demoDescObj.Name = EID:getDescriptionEntry("AchievementWarningTitle") or ""
-						demoDescObj.Description = EID:getDescriptionEntry("AchievementWarningText") or ""
-						EID:displayPermanentText(demoDescObj)
-						hasShownAchievementWarning = true
-					end
+	if REPENTANCE and not EID.Config.DisableAchievementCheck and game:GetFrameCount() < 10*30 and game.Challenge == 0 then
+		local characterID = Game():GetPlayer(0):GetPlayerType()
+		--ID 21 = Tainted Isaac. Tainted characters have definitely beaten Mom! (Fixes Tainted Lost's item pools ruining this check)
+		if characterID < 21 then
+			local hasBookOfRevelationsUnlocked = EID:isCollectibleUnlockedAnyPool(CollectibleType.COLLECTIBLE_BOOK_OF_REVELATIONS or CollectibleType.COLLECTIBLE_BOOK_REVELATIONS)
+			if not hasBookOfRevelationsUnlocked then
+				local hasCubeOfMeatUnlocked = EID:isCollectibleUnlockedAnyPool(CollectibleType.COLLECTIBLE_CUBE_OF_MEAT)
+				if not hasCubeOfMeatUnlocked then
+					local demoDescObj = EID:getDescriptionObj(-999, -1, 1)
+					demoDescObj.Name = EID:getDescriptionEntry("AchievementWarningTitle") or ""
+					demoDescObj.Description = EID:getDescriptionEntry("AchievementWarningText") or ""
+					EID:displayPermanentText(demoDescObj)
+					hasShownAchievementWarning = true
 				end
 			end
 		end