diff --git a/basis/lib.lua b/basis/lib.lua
index d47f5ac..6bf49dc 100644
--- a/basis/lib.lua
+++ b/basis/lib.lua
@@ -244,6 +244,17 @@ function techage.add_to_set(set, x)
 	end
 end
 
+-- techage.tbl_filter({"a", "b", "c", "d"}, function(v, k, t) return v >= "c" end)  --> {"c","d"}
+techage.tbl_filter = function(t, filterIter)
+	local out = {}
+
+	for k, v in pairs(t) do
+		if filterIter(v, k, t) then out[k] = v end
+	end
+
+	return out
+end
+
 function techage.get_node_lvm(pos)
 	local node = minetest.get_node_or_nil(pos)
 	if node then
diff --git a/basis/nodedata_meta.lua b/basis/nodedata_meta.lua
index 875ce6d..5128080 100644
--- a/basis/nodedata_meta.lua
+++ b/basis/nodedata_meta.lua
@@ -17,37 +17,8 @@ local M = minetest.get_meta
 
 local storage = techage.storage
 
--------------------------------------------------------------------
--- Marshaling
--------------------------------------------------------------------
-local use_marshal = minetest.settings:get_bool('techage_use_marshal', false)
-local MAR_MAGIC = 0x8e
-
--- default functions
-local serialize = minetest.serialize
-local deserialize = minetest.deserialize
-
-if use_marshal then
-	if not techage.IE then
-		error("Please add 'secure.trusted_mods = techage' to minetest.conf!")
-	end
-	local marshal = techage.IE.require("marshal")
-	if not marshal then
-		error("Please install marshal via 'luarocks install lua-marshal'")
-	end
-
-	serialize = marshal.encode
-
-	deserialize = function(s)
-		if s ~= "" then
-			if s:byte(1) == MAR_MAGIC then
-				return marshal.decode(s)
-			else
-				return minetest.deserialize(s)
-			end
-		end
-	end
-end
+local MP = minetest.get_modpath("techage")
+local serialize, deserialize = dofile(MP .. "/basis/marshal.lua")
 
 -------------------------------------------------------------------
 -- API functions
@@ -86,15 +57,17 @@ function api.get_node_data(pos)
 end
 
 -- Meta data can't be written reliable at shutdown,
--- so we have to store/restore the data differently
+-- so we have to store/restore the data differently.
 function api.freeze_at_shutdown(data)
-	storage:set_string("shutdown_nodedata", serialize(data))
+	-- We use the minetest serialize function, because marshal.encode
+        -- generates a binary string, which can't be stored in storage.
+	storage:set_string("shutdown_nodedata", minetest.serialize(data))
 end
 
 function api.restore_at_startup()
 	local s = storage:get_string("shutdown_nodedata")
 	if s ~= "" then
-		return deserialize(s) or {}
+		return minetest.deserialize(s) or {}
 	end
 	return {}
 end
diff --git a/basis/nodedata_sqlite.lua b/basis/nodedata_sqlite.lua
index e9e3f8c..fae7aaf 100644
--- a/basis/nodedata_sqlite.lua
+++ b/basis/nodedata_sqlite.lua
@@ -18,23 +18,17 @@ local M = minetest.get_meta
 -------------------------------------------------------------------
 -- Database
 -------------------------------------------------------------------
-local MN = minetest.get_current_modname()
 local WP = minetest.get_worldpath()
-local MAR_MAGIC = 0x8e
 
 if not techage.IE then
 	error("Please add 'secure.trusted_mods = techage' to minetest.conf!")
 end
 
 local sqlite3 = techage.IE.require("lsqlite3")
-local marshal = techage.IE.require("marshal")
 
 if not sqlite3 then
 	error("Please install sqlite3 via 'luarocks install lsqlite3'")
 end
-if not marshal then
-	error("Please install marshal via 'luarocks install lua-marshal'")
-end
 
 local db = sqlite3.open(WP.."/techage_nodedata.sqlite")
 local ROW = sqlite3.ROW
@@ -71,21 +65,18 @@ end
 -------------------------------------------------------------------
 local api = {}
 
+local MP = minetest.get_modpath("techage")
+local serialize, deserialize = dofile(MP .. "/basis/marshal.lua")
+
 function api.store_mapblock_data(key, mapblock_data)
-	-- deactivated due to weird server crashes without error logs
-	--local s = marshal.encode(mapblock_data)
-	local s = minetest.serialize(mapblock_data)
+	local s = serialize(mapblock_data)
 	return set_block(key, s)
 end
 
 function api.get_mapblock_data(key)
 	local s = get_block(key)
 	if s then
-		if s:byte(1) == MAR_MAGIC then
-			return marshal.decode(s)
-		else
-			return minetest.deserialize(s)
-		end
+		return deserialize(s)
 	end
 	api.store_mapblock_data(key, {})
 	return {}
@@ -96,11 +87,7 @@ function api.get_node_data(pos)
 	local s = M(pos):get_string("ta_data")
 	if s ~= "" then
 		M(pos):set_string("ta_data", "")
-		if s:byte(1) == MAR_MAGIC then
-			return marshal.decode(s)
-		else
-			return minetest.deserialize(s)
-		end
+		return deserialize(s)
 	end
 	return {}
 end
diff --git a/basis/numbers_sqlite.lua b/basis/numbers_sqlite.lua
index f2f8be8..58b0291 100644
--- a/basis/numbers_sqlite.lua
+++ b/basis/numbers_sqlite.lua
@@ -12,31 +12,22 @@
 
 ]]--
 
--- for lazy programmers
-local M = minetest.get_meta
-
 local storage = techage.storage
 
 -------------------------------------------------------------------
 -- Database
 -------------------------------------------------------------------
-local MN = minetest.get_current_modname()
 local WP = minetest.get_worldpath()
-local MAR_MAGIC = 0x8e
 
 if not techage.IE then
 	error("Please add 'secure.trusted_mods = techage' to minetest.conf!")
 end
 
 local sqlite3 = techage.IE.require("lsqlite3")
-local marshal = techage.IE.require("marshal")
 
 if not sqlite3 then
 	error("Please install sqlite3 via 'luarocks install lsqlite3'")
 end
-if not marshal then
-	error("Please install marshal via 'luarocks install lua-marshal'")
-end
 
 local db = sqlite3.open(WP.."/techage_numbers.sqlite")
 local ROW = sqlite3.ROW
@@ -129,7 +120,7 @@ end
 -- delete invalid entries
 function api.delete_invalid_entries(node_def)
 	minetest.log("info", "[TechAge] Data maintenance started")
-	for id, num, x, y, z in db:urows('SELECT * FROM numbers') do
+	for _, num, x, y, z in db:urows('SELECT * FROM numbers') do
 		local pos = {x = x, y = y, z = z}
 		local name = techage.get_node_lvm(pos).name
 		if not node_def[name] then
diff --git a/fusion_reactor/controller.lua b/fusion_reactor/controller.lua
index 848cdaf..8af0bd8 100644
--- a/fusion_reactor/controller.lua
+++ b/fusion_reactor/controller.lua
@@ -46,6 +46,7 @@ local function count_trues(t)
 end
 
 local function nucleus(t)
+	t = techage.tbl_filter(t, function(v, k, t) return type(v) == "table" end)
 	if #t == 4 then
 		if vector.equals(t[1], t[2]) and vector.equals(t[3], t[4]) then
 			return true