diff --git a/Firmware/Configuration_adv.h b/Firmware/Configuration_adv.h
index 7f25f07d5..d25b345c3 100644
--- a/Firmware/Configuration_adv.h
+++ b/Firmware/Configuration_adv.h
@@ -287,6 +287,7 @@
 
 #ifdef LIN_ADVANCE
   #define LIN_ADVANCE_K 0  // Unit: mm compression per 1mm/s extruder speed
+  //#define LA_NOCOMPAT    // Disable Linear Advance 1.0 compatibility
   //#define LA_LIVE_K      // Allow adjusting K in the Tune menu
   //#define LA_DEBUG       // If enabled, this will generate debug information output over USB.
   //#define LA_DEBUG_LOGIC // @wavexx: setup logic channels for isr debugging
diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index 816763ac1..8959bdd31 100755
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -83,6 +83,9 @@
 #include "Dcodes.h"
 #include "AutoDeplete.h"
 
+#ifndef LA_NOCOMPAT
+#include "la10compat.h"
+#endif
 
 #ifdef SWSPI
 #include "swspi.h"
@@ -2068,12 +2071,23 @@ static float probe_pt(float x, float y, float z_before) {
     */
 inline void gcode_M900() {
     st_synchronize();
-    
+
     const float newK = code_seen('K') ? code_value_float() : -1;
+#ifdef LA_NOCOMPAT
     if (newK >= 0 && newK < 10)
-      extruder_advance_K = newK;
+        extruder_advance_K = newK;
     else
-      SERIAL_ECHOLNPGM("K out of allowed range!");
+        SERIAL_ECHOLNPGM("K out of allowed range!");
+#else
+    if (newK == 0) {
+        la10c_reset();
+        extruder_advance_K = 0;
+    }
+    else if(newK > 0)
+        extruder_advance_K = la10c_value(newK);
+    else
+        SERIAL_ECHOLNPGM("K out of allowed range!");
+#endif
 
     SERIAL_ECHO_START;
     SERIAL_ECHOPGM("Advance K=");
@@ -4136,6 +4150,9 @@ if(eSoundMode!=e_SOUND_MODE_SILENT)
     // --------------------------------------------
     case 28: 
     {
+#ifndef LA_NOCOMPAT
+      la10c_reset();
+#endif
       long home_x_value = 0;
       long home_y_value = 0;
       long home_z_value = 0;
@@ -5372,6 +5389,9 @@ if(eSoundMode!=e_SOUND_MODE_SILENT)
       else
       {
           failstats_reset_print();
+#ifndef LA_NOCOMPAT
+          la10c_reset();
+#endif
           card.startFileprint();
           starttime=_millis();
       }
@@ -5465,6 +5485,9 @@ if(eSoundMode!=e_SOUND_MODE_SILENT)
         if(code_seen('S'))
           if(strchr_pointer<namestartpos) //only if "S" is occuring _before_ the filename
             card.setIndex(code_value_long());
+#ifndef LA_NOCOMPAT
+        la10c_reset();
+#endif
         card.startFileprint();
         if(!call_procedure)
           starttime=_millis(); //procedure calls count as normal print time.
diff --git a/Firmware/la10compat.cpp b/Firmware/la10compat.cpp
new file mode 100644
index 000000000..41c3a8e6f
--- /dev/null
+++ b/Firmware/la10compat.cpp
@@ -0,0 +1,40 @@
+#include "la10compat.h"
+#include "Marlin.h"
+
+
+static LA10C_MODE la10c_mode = LA10C_UNKNOWN;
+
+
+void la10c_mode_change(LA10C_MODE mode)
+{
+    if(mode == la10c_mode) return;
+
+    SERIAL_ECHOPGM("LA10C: Linear Advance mode: ");
+    switch(mode)
+    {
+    case LA10C_UNKNOWN: SERIAL_ECHOLNPGM("UNKNOWN"); break;
+    case LA10C_LA15:    SERIAL_ECHOLNPGM("1.5"); break;
+    case LA10C_LA10:    SERIAL_ECHOLNPGM("1.0"); break;
+    }
+    la10c_mode = mode;
+}
+
+
+// Approximate a LA10 value to a LA15 equivalent.
+static float la10c_convert(float k)
+{
+    float new_K = k * 0.004 - 0.06;
+    return (new_K < 0? 0: new_K);
+}
+
+
+float la10c_value(float k)
+{
+    if(la10c_mode == LA10C_UNKNOWN)
+        la10c_mode_change(k < 10? LA10C_LA15: LA10C_LA10);
+
+    if(la10c_mode == LA10C_LA15)
+        return k;
+    else
+        return la10c_convert(k);
+}
diff --git a/Firmware/la10compat.h b/Firmware/la10compat.h
new file mode 100644
index 000000000..e6ffbc37b
--- /dev/null
+++ b/Firmware/la10compat.h
@@ -0,0 +1,39 @@
+// la10compat: LA10->LA15 conversion
+//
+// When the current mode is UNKNOWN autodetection is active and any K<10
+// will set the mode to LA15, LA10 is set otherwise. When LA10
+// compatbility mode is active the K factor is converted to a LA15
+// equivalent (that is, the return value is always a LA15 value).
+//
+// Once the interpretation mode has been set it is kept until the mode
+// is explicitly reset. This is done to handle transparent fallback for
+// old firmware revisions in combination with the following gcode
+// sequence:
+//
+//   M900 K0.01 ; set LA15 value (interpreted by any firmware)
+//   M900 K10   ; set LA10 value (ignored by LA15 firmware)
+//
+// A LA15 firmware without this module will only parse the first
+// correctly, rejecting the second. A LA10 FW will parse both, but keep
+// the last value. Since the LA15 value, if present, corresponds to the
+// truth value, the compatibility stub needs to "lock" onto the first
+// seen value for the current print.
+//
+// The mode needs to be carefully reset for each print in order for
+// diffent versions of M900 to be interpreted independently.
+
+#pragma once
+
+enum __attribute__((packed)) LA10C_MODE
+{
+    LA10C_UNKNOWN = 0,
+    LA10C_LA15    = 1,
+    LA10C_LA10    = 2
+};
+
+// Explicitly set/reset the interpretation mode for la10c_value()
+void la10c_mode_change(LA10C_MODE mode);
+static inline void la10c_reset() { la10c_mode_change(LA10C_UNKNOWN); }
+
+// Return a LA15 K value according to the supplied value and mode
+float la10c_value(float k);