diff --git a/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp b/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
index 262dcea364..e2f11502e7 100644
--- a/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
@@ -46,6 +46,12 @@
 
 DGUSDisplay dgusdisplay;
 
+#ifdef DEBUG_DGUSLCD_COMM
+  #define DEBUGLCDCOMM_ECHOPGM DEBUG_ECHOPGM
+#else
+  #define DEBUGLCDCOMM_ECHOPGM(...) NOOP
+#endif
+
 // Preamble... 2 Bytes, usually 0x5A 0xA5, but configurable
 constexpr uint8_t DGUS_HEADER1 = 0x5A;
 constexpr uint8_t DGUS_HEADER2 = 0xA5;
@@ -154,19 +160,19 @@ void DGUSDisplay::ProcessRx() {
 
       case DGUS_IDLE: // Waiting for the first header byte
         receivedbyte = LCD_SERIAL.read();
-        //DEBUG_ECHOPGM("< ",x);
+        //DEBUGLCDCOMM_ECHOPGM("< ", receivedbyte);
         if (DGUS_HEADER1 == receivedbyte) rx_datagram_state = DGUS_HEADER1_SEEN;
         break;
 
       case DGUS_HEADER1_SEEN: // Waiting for the second header byte
         receivedbyte = LCD_SERIAL.read();
-        //DEBUG_ECHOPGM(" ",x);
+        //DEBUGLCDCOMM_ECHOPGM(" ", receivedbyte);
         rx_datagram_state = (DGUS_HEADER2 == receivedbyte) ? DGUS_HEADER2_SEEN : DGUS_IDLE;
         break;
 
       case DGUS_HEADER2_SEEN: // Waiting for the length byte
         rx_datagram_len = LCD_SERIAL.read();
-        DEBUG_ECHOPGM(" (", rx_datagram_len, ") ");
+        //DEBUGLCDCOMM_ECHOPGM(" (", rx_datagram_len, ") ");
 
         // Telegram min len is 3 (command and one word of payload)
         rx_datagram_state = WITHIN(rx_datagram_len, 3, DGUS_RX_BUFFER_SIZE) ? DGUS_WAIT_TELEGRAM : DGUS_IDLE;
@@ -178,20 +184,20 @@ void DGUSDisplay::ProcessRx() {
         Initialized = true; // We've talked to it, so we defined it as initialized.
         uint8_t command = LCD_SERIAL.read();
 
-        DEBUG_ECHOPGM("# ", command);
+        //DEBUGLCDCOMM_ECHOPGM("# ", command);
 
         uint8_t readlen = rx_datagram_len - 1;  // command is part of len.
         unsigned char tmp[rx_datagram_len - 1];
         unsigned char *ptmp = tmp;
         while (readlen--) {
           receivedbyte = LCD_SERIAL.read();
-          DEBUG_ECHOPGM(" ", receivedbyte);
+          //DEBUGLCDCOMM_ECHOPGM(" ", receivedbyte);
           *ptmp++ = receivedbyte;
         }
-        DEBUG_ECHOPGM(" # ");
+        //DEBUGLCDCOMM_ECHOPGM(" # ");
         // mostly we'll get this: 5A A5 03 82 4F 4B -- ACK on 0x82, so discard it.
         if (command == DGUS_CMD_WRITEVAR && 'O' == tmp[0] && 'K' == tmp[1]) {
-          DEBUG_ECHOLNPGM(">");
+          //DEBUGLCDCOMM_ECHOPGM(">");
           rx_datagram_state = DGUS_IDLE;
           break;
         }
@@ -253,16 +259,16 @@ void DGUSDisplay::loop() {
 
 rx_datagram_state_t DGUSDisplay::rx_datagram_state = DGUS_IDLE;
 uint8_t DGUSDisplay::rx_datagram_len = 0;
-bool DGUSDisplay::Initialized = false;
-bool DGUSDisplay::no_reentrance = false;
+bool DGUSDisplay::Initialized = false,
+     DGUSDisplay::no_reentrance = false;
 
 // A SW memory barrier, to ensure GCC does not overoptimize loops
 #define sw_barrier() asm volatile("": : :"memory");
 
 bool populate_VPVar(const uint16_t VP, DGUS_VP_Variable * const ramcopy) {
-  // DEBUG_ECHOPGM("populate_VPVar ", VP);
+  //DEBUG_ECHOPGM("populate_VPVar ", VP);
   const DGUS_VP_Variable *pvp = DGUSLCD_FindVPVar(VP);
-  // DEBUG_ECHOLNPGM(" pvp ", (uint16_t )pvp);
+  //DEBUG_ECHOLNPGM(" pvp ", (uint16_t )pvp);
   if (!pvp) return false;
   memcpy_P(ramcopy, pvp, sizeof(DGUS_VP_Variable));
   return true;
diff --git a/Marlin/src/lcd/extui/dgus/DGUSDisplay.h b/Marlin/src/lcd/extui/dgus/DGUSDisplay.h
index 3040225d07..17303c689b 100644
--- a/Marlin/src/lcd/extui/dgus/DGUSDisplay.h
+++ b/Marlin/src/lcd/extui/dgus/DGUSDisplay.h
@@ -29,6 +29,9 @@
 
 #include <stdlib.h>    // size_t
 
+//#define DEBUG_DGUSLCD
+//#define DEBUG_DGUSLCD_COMM
+
 #if HAS_BED_PROBE
   #include "../../../module/probe.h"
 #endif
diff --git a/Marlin/src/lcd/extui/dgus/DGUSScreenHandler.cpp b/Marlin/src/lcd/extui/dgus/DGUSScreenHandler.cpp
index 70bcca1859..9b25f8aeb1 100644
--- a/Marlin/src/lcd/extui/dgus/DGUSScreenHandler.cpp
+++ b/Marlin/src/lcd/extui/dgus/DGUSScreenHandler.cpp
@@ -55,14 +55,14 @@ void (*DGUSScreenHandler::confirm_action_cb)() = nullptr;
 #if ENABLED(SDSUPPORT)
   int16_t DGUSScreenHandler::top_file = 0,
           DGUSScreenHandler::file_to_print = 0;
-  static ExtUI::FileList filelist;
+  ExtUI::FileList filelist;
 #endif
 
 #if ENABLED(DGUS_FILAMENT_LOADUNLOAD)
   filament_data_t filament_data;
 #endif
 
-void DGUSScreenHandler::sendinfoscreen(const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool l4inflash) {
+void DGUSScreenHandler::sendinfoscreen(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool l4inflash) {
   DGUS_VP_Variable ramcopy;
   if (populate_VPVar(VP_MSGSTR1, &ramcopy)) {
     ramcopy.memadr = (void*) line1;
@@ -76,13 +76,15 @@ void DGUSScreenHandler::sendinfoscreen(const char *line1, const char *line2, con
     ramcopy.memadr = (void*) line3;
     l3inflash ? DGUSScreenHandler::DGUSLCD_SendStringToDisplayPGM(ramcopy) : DGUSScreenHandler::DGUSLCD_SendStringToDisplay(ramcopy);
   }
-  if (populate_VPVar(VP_MSGSTR4, &ramcopy)) {
-    ramcopy.memadr = (void*) line4;
-    l4inflash ? DGUSScreenHandler::DGUSLCD_SendStringToDisplayPGM(ramcopy) : DGUSScreenHandler::DGUSLCD_SendStringToDisplay(ramcopy);
-  }
+  #ifdef VP_MSGSTR4
+    if (populate_VPVar(VP_MSGSTR4, &ramcopy)) {
+      ramcopy.memadr = (void*) line4;
+      l4inflash ? DGUSScreenHandler::DGUSLCD_SendStringToDisplayPGM(ramcopy) : DGUSScreenHandler::DGUSLCD_SendStringToDisplay(ramcopy);
+    }
+  #endif
 }
 
-void DGUSScreenHandler::HandleUserConfirmationPopUp(uint16_t VP, const char *line1, const char *line2, const char *line3, const char *line4, bool l1, bool l2, bool l3, bool l4) {
+void DGUSScreenHandler::HandleUserConfirmationPopUp(uint16_t VP, PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1, bool l2, bool l3, bool l4) {
   if (current_screen == DGUSLCD_SCREEN_CONFIRM) // Already showing a pop up, so we need to cancel that first.
     PopToOldScreen();
 
@@ -344,6 +346,7 @@ void DGUSScreenHandler::DGUSLCD_SendHeaterStatusToDisplay(DGUS_VP_Variable &var)
     SetupConfirmAction(nullptr);
     GotoScreen(DGUSLCD_SCREEN_POPUP);
   }
+
 #endif // SDSUPPORT
 
 void DGUSScreenHandler::ScreenConfirmedOK(DGUS_VP_Variable &var, void *val_ptr) {
diff --git a/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.cpp b/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.cpp
index eba4b153f1..e7466bfe08 100644
--- a/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.cpp
+++ b/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.cpp
@@ -42,7 +42,7 @@
 
 #if ENABLED(SDSUPPORT)
 
-  static ExtUI::FileList filelist;
+  extern ExtUI::FileList filelist;
 
   void DGUSScreenHandler::DGUSLCD_SD_FileSelected(DGUS_VP_Variable &var, void *val_ptr) {
     uint16_t touched_nr = (int16_t)swap16(*(uint16_t*)val_ptr) + top_file;
diff --git a/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.h b/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.h
index d4fdf1d27e..0bdf06ed7d 100644
--- a/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.h
+++ b/Marlin/src/lcd/extui/dgus/fysetc/DGUSScreenHandler.h
@@ -37,15 +37,15 @@ public:
 
   // Send all 4 strings that are displayed on the infoscreen, confirmation screen and kill screen
   // The bools specifying whether the strings are in RAM or FLASH.
-  static void sendinfoscreen(const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
-  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
+  static void sendinfoscreen(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), line3, line4, l1inflash, l2inflash, l3inflash, liinflash);
   }
   static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, FSTR_P const line3, FSTR_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), FTOP(line3), FTOP(line4), l1inflash, l2inflash, l3inflash, liinflash);
   }
 
-  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
 
   // "M117" Message -- msg is a RAM ptr.
   static void setstatusmessage(const char *msg);
diff --git a/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.cpp b/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.cpp
index 88b3255b66..d64ac143b0 100644
--- a/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.cpp
+++ b/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.cpp
@@ -42,7 +42,7 @@
 
 #if ENABLED(SDSUPPORT)
 
-  static ExtUI::FileList filelist;
+  extern ExtUI::FileList filelist;
 
   void DGUSScreenHandler::DGUSLCD_SD_FileSelected(DGUS_VP_Variable &var, void *val_ptr) {
     uint16_t touched_nr = (int16_t)swap16(*(uint16_t*)val_ptr) + top_file;
diff --git a/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.h b/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.h
index d4fdf1d27e..0bdf06ed7d 100644
--- a/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.h
+++ b/Marlin/src/lcd/extui/dgus/hiprecy/DGUSScreenHandler.h
@@ -37,15 +37,15 @@ public:
 
   // Send all 4 strings that are displayed on the infoscreen, confirmation screen and kill screen
   // The bools specifying whether the strings are in RAM or FLASH.
-  static void sendinfoscreen(const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
-  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
+  static void sendinfoscreen(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), line3, line4, l1inflash, l2inflash, l3inflash, liinflash);
   }
   static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, FSTR_P const line3, FSTR_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), FTOP(line3), FTOP(line4), l1inflash, l2inflash, l3inflash, liinflash);
   }
 
-  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
 
   // "M117" Message -- msg is a RAM ptr.
   static void setstatusmessage(const char *msg);
diff --git a/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.cpp b/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.cpp
index e729ecf441..91746f69c4 100644
--- a/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.cpp
+++ b/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.cpp
@@ -48,7 +48,7 @@
 #endif
 
 #if ENABLED(SDSUPPORT)
-  static ExtUI::FileList filelist;
+  extern ExtUI::FileList filelist;
 #endif
 
 bool DGUSAutoTurnOff = false;
@@ -65,7 +65,7 @@ void DGUSScreenHandler::sendinfoscreen_ch_mks(const uint16_t *line1, const uint1
   dgusdisplay.WriteVariable(VP_MSGSTR4, line4, 32, true);
 }
 
-void DGUSScreenHandler::sendinfoscreen_en_mks(const char *line1, const char *line2, const char *line3, const char *line4) {
+void DGUSScreenHandler::sendinfoscreen_en_mks(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4) {
   dgusdisplay.WriteVariable(VP_MSGSTR1, line1, 32, true);
   dgusdisplay.WriteVariable(VP_MSGSTR2, line2, 32, true);
   dgusdisplay.WriteVariable(VP_MSGSTR3, line3, 32, true);
diff --git a/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.h b/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.h
index 2e6c8af985..f14604d01a 100644
--- a/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.h
+++ b/Marlin/src/lcd/extui/dgus/mks/DGUSScreenHandler.h
@@ -37,19 +37,19 @@ public:
 
   // Send all 4 strings that are displayed on the infoscreen, confirmation screen and kill screen
   // The bools specifying whether the strings are in RAM or FLASH.
-  static void sendinfoscreen(const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
-  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
+  static void sendinfoscreen(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), line3, line4, l1inflash, l2inflash, l3inflash, liinflash);
   }
   static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, FSTR_P const line3, FSTR_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), FTOP(line3), FTOP(line4), l1inflash, l2inflash, l3inflash, liinflash);
   }
 
-  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
 
   #if 0
   static void sendinfoscreen_ch_mks(const uint16_t *line1, const uint16_t *line2, const uint16_t *line3, const uint16_t *line4);
-  static void sendinfoscreen_en_mks(const char *line1, const char *line2, const char *line3, const char *line4) ;
+  static void sendinfoscreen_en_mks(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4);
   static void sendinfoscreen_mks(const void *line1, const void *line2, const void *line3, const void *line4, uint16_t language);
   #endif
 
diff --git a/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.cpp b/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.cpp
index fb08fbf849..aaa8b72e11 100644
--- a/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.cpp
+++ b/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.cpp
@@ -42,7 +42,7 @@
 
 #if ENABLED(SDSUPPORT)
 
-  static ExtUI::FileList filelist;
+  extern ExtUI::FileList filelist;
 
   void DGUSScreenHandler::DGUSLCD_SD_FileSelected(DGUS_VP_Variable &var, void *val_ptr) {
     uint16_t touched_nr = (int16_t)swap16(*(uint16_t*)val_ptr) + top_file;
diff --git a/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.h b/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.h
index d4fdf1d27e..0bdf06ed7d 100644
--- a/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.h
+++ b/Marlin/src/lcd/extui/dgus/origin/DGUSScreenHandler.h
@@ -37,15 +37,15 @@ public:
 
   // Send all 4 strings that are displayed on the infoscreen, confirmation screen and kill screen
   // The bools specifying whether the strings are in RAM or FLASH.
-  static void sendinfoscreen(const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
-  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
+  static void sendinfoscreen(PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), line3, line4, l1inflash, l2inflash, l3inflash, liinflash);
   }
   static void sendinfoscreen(FSTR_P const line1, FSTR_P const line2, FSTR_P const line3, FSTR_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash) {
     sendinfoscreen(FTOP(line1), FTOP(line2), FTOP(line3), FTOP(line4), l1inflash, l2inflash, l3inflash, liinflash);
   }
 
-  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, const char *line1, const char *line2, const char *line3, const char *line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
+  static void HandleUserConfirmationPopUp(uint16_t ConfirmVP, PGM_P const line1, PGM_P const line2, PGM_P const line3, PGM_P const line4, bool l1inflash, bool l2inflash, bool l3inflash, bool liinflash);
 
   // "M117" Message -- msg is a RAM ptr.
   static void setstatusmessage(const char *msg);