diff --git a/parts/data.lua b/parts/data.lua
index aee0555e..c7dc7ad2 100644
--- a/parts/data.lua
+++ b/parts/data.lua
@@ -99,6 +99,7 @@ function DATA.pasteBoard(str)-- Paste [str] data to [page] board
 
     local fX,fY=1,1-- *ptr for Field(r*10+(c-1))
     local p=1
+    local lineLimit=126
     while true do
         local b=byte(str,p)-- 1byte
 
@@ -120,13 +121,13 @@ function DATA.pasteBoard(str)-- Paste [str] data to [page] board
             fX=fX+1
         else
             fY=fY+1
-            if fY>126 then break end
+            if fY>lineLimit then break end
             fX=1
         end
         p=p+1
     end
 
-    return true, F
+    return true, F, #str>lineLimit*10
 end
 
 --[[
@@ -213,9 +214,26 @@ function DATA.pasteQuestArgs(str)
     if #str<4 then return end
     local ENV={}
     ENV.holdCount=  str:byte(1)-48
+    if ENV.holdCount<0 or ENV.holdCount>6 then
+        -- hold count invalid
+        if ENV.holdCount>=7 and ENV.holdCount<=9 then
+            -- hold count clearly intended to be a number, set to 6
+            ENV.holdCount=6
+            MES.new('warn',text.customDataInvalidHold1)
+        else
+            -- hold count is a random character, reset to 1
+            ENV.holdCount=1
+            MES.new('warn',text.customDataInvalidHold2)
+        end
+    end
     ENV.ospin=      str:byte(2)~=90
     ENV.missionKill=str:byte(3)~=90
     ENV.sequence=   str:sub(4)
+    -- hard coding list of generators because there is no other way to obtain it
+    if not TABLE.find({'bag','bagES','his','hisPool','c2','bagP1inf','rnd','mess','reverb','loop','fixed'}, ENV.sequence) then
+        MES.new('warn',text.customDataInvalidSequence)
+        ENV.sequence='bag'
+    end
     return true,ENV
 end
 
diff --git a/parts/language/lang_en.lua b/parts/language/lang_en.lua
index fec20580..9ff7b6c6 100644
--- a/parts/language/lang_en.lua
+++ b/parts/language/lang_en.lua
@@ -95,6 +95,13 @@ return {
     dataCorrupted="Data corrupted",
     pasteWrongPlace="Did you paste in the wrong place?",
     noFile="File missing",
+    
+    -- data validation for custom game data import
+    customDataInvalidHold1="Invalid Hold queue length in custom mode data. Resetting to 6.",
+    customDataInvalidHold2="Invalid Hold queue length in custom mode data. Resetting to 1.",
+    customDataInvalidSequence="Invalid sequence mode in custom mode data. Resetting to bag.",
+    customDataBoardLineLimit="One or more fields in the data exceeded height limit (126 lines).\nParts exceeding the limit have been removed.",
+    customDataSingleBoardLineLimit="Field data exceeded height limit (126 lines).\nParts exceeding the limit have been removed.",
 
     nowPlaying="Now playing:",
 
diff --git a/parts/language/lang_zh.lua b/parts/language/lang_zh.lua
index 9b600219..aa7a9a78 100644
--- a/parts/language/lang_zh.lua
+++ b/parts/language/lang_zh.lua
@@ -95,6 +95,13 @@ return {
     dataCorrupted="数据损坏",
     pasteWrongPlace="提醒:可能粘贴错地方了",
     noFile="找不到文件",
+    
+    -- data validation for custom game data import
+    customDataInvalidHold1="自定义模式数据中的 Hold 数量错误。重置为 6。",
+    customDataInvalidHold2="自定义模式数据中的 Hold 数量错误。重置为 1。",
+    customDataInvalidSequence="自定义模式数据中的序列模式不存在。重置为 bag。",
+    customDataBoardLineLimit="数据中一个或多个自定义场地的高度超过限制（126 行）。超出限制的部分已被移除。",
+    customDataSingleBoardLineLimit="数据中自定义场地的高度超过限制（126 行）。超出限制的部分已被移除。",
 
     nowPlaying="正在播放:",
 
diff --git a/parts/scenes/customGame.lua b/parts/scenes/customGame.lua
index 59ea064d..a127207c 100644
--- a/parts/scenes/customGame.lua
+++ b/parts/scenes/customGame.lua
@@ -191,6 +191,7 @@ function scene.keyDown(key,isRep)
     elseif key=='v' and kb.isDown('lctrl','rctrl') or key=='cV' then
         local str=sys.getClipboardText()
         local args=str:sub((str:find(":") or 0)+1):split("!")
+        local flagHasBoardWithLineLimit=false
         repeat
             if #args<4 then break end-- goto THROW_fail
             local success,env=DATA.pasteQuestArgs(args[1])
@@ -210,15 +211,22 @@ function scene.keyDown(key,isRep)
             TABLE.cut(CUSTOMGAME_LOCAL.field)
             CUSTOMGAME_LOCAL.field[1]=DATA.newBoard()
             for i=4,#args do
+                
                 if args[i]:find("%S") then
-                    local success,F=DATA.pasteBoard(args[i])
+                    local success, F, flagBoardLineLimit=DATA.pasteBoard(args[i])
                     if success then
+                        if flagBoardLineLimit then
+                            flagHasBoardWithLineLimit=true
+                        end
                         CUSTOMGAME_LOCAL.field[i-3]=F
                     else
                         if i<#args then break end-- goto THROW_fail
                     end
                 end
             end
+            if flagHasBoardWithLineLimit then
+                MES.new('warn', text.customDataBoardLineLimit)
+            end
             MES.new('check',text.importSuccess)
             return
         until true
diff --git a/parts/scenes/custom_field.lua b/parts/scenes/custom_field.lua
index b90f5170..426e7e16 100644
--- a/parts/scenes/custom_field.lua
+++ b/parts/scenes/custom_field.lua
@@ -237,9 +237,12 @@ function scene.keyDown(key)
             end
             str=str:sub(p+1)
         end
-        local success,F=DATA.pasteBoard(str)
+        local success,F, flagBoardLineLimit=DATA.pasteBoard(str)
         if success then
             FIELD[page]=F
+            if flagBoardLineLimit then
+                MES.new('warn', text.customDataSingleBoardLineLimit)
+            end
             MES.new('check',text.importSuccess)
         else
             MES.new('error',text.dataCorrupted)