diff --git a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/player/SurvivalFly.java b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/player/SurvivalFly.java
index 6bb5bbeb..949d4db4 100644
--- a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/player/SurvivalFly.java
+++ b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/player/SurvivalFly.java
@@ -245,6 +245,14 @@ public class SurvivalFly extends Check {
                 //                    || to.isHeadObstructed() // Best not have this one.
                 ;
         //}
+        
+        // HACK: Force sfNoLowJump by a flag.
+        // TODO: Might remove that flag, as the issue for trying this has been resolved differently (F_HEIGHT8_1).
+        // TODO: Consider setting on ground_height always?
+        if ((from.getBlockFlags() & BlockProperties.F_ALLOW_LOWJUMP) != 0) {
+            // TODO: Specialize - test for foot region?
+            data.sfNoLowJump = true;
+        }
 
         //////////////////////
         // Horizontal move.
diff --git a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/utilities/map/BlockProperties.java b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/utilities/map/BlockProperties.java
index 2ba66ac2..0e98b759 100644
--- a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/utilities/map/BlockProperties.java
+++ b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/utilities/map/BlockProperties.java
@@ -587,6 +587,14 @@ public class BlockProperties {
      */
     public static final long F_ATTACHED_LOW2_SNEW       = 0x2000000;
 
+    /**
+     * The hacky way to force sfNoLowJump when the block at from has this flag.
+     */
+    public static final long F_ALLOW_LOWJUMP            = 0x4000000;
+
+    /** One eighth block height (0.125). */
+    public static final long F_HEIGHT8_1            = 0x8000000;
+
     // TODO: When flags are out, switch to per-block classes :p.
 
     // Special case activation flags.
@@ -3274,6 +3282,10 @@ public class BlockProperties {
                     bmaxY = shouldLiquidBelowBeFullHeight(access, x, y + 1, z) ? 1.0 : LIQUID_HEIGHT_LOWERED;
                 }
             }
+            else if ((flags & F_HEIGHT8_1) != 0) {
+                bminY = 0.0;
+                bmaxY = 0.125;
+            }
             else if (id == Material.ENDER_PORTAL_FRAME.getId()) {
                 // TODO: Test
                 // TODO: Other concepts ...