diff --git a/target/arm/internals.h b/target/arm/internals.h
index 3d3d41ba2b..00af41d792 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -462,28 +462,51 @@ static inline uint32_t arm_fi_to_lfsc(ARMMMUFaultInfo *fi)
     case ARMFault_None:
         return 0;
     case ARMFault_AddressSize:
-        fsc = fi->level & 3;
+        assert(fi->level >= -1 && fi->level <= 3);
+        if (fi->level < 0) {
+            fsc = 0b101001;
+        } else {
+            fsc = fi->level;
+        }
         break;
     case ARMFault_AccessFlag:
-        fsc = (fi->level & 3) | (0x2 << 2);
+        assert(fi->level >= 0 && fi->level <= 3);
+        fsc = 0b001000 | fi->level;
         break;
     case ARMFault_Permission:
-        fsc = (fi->level & 3) | (0x3 << 2);
+        assert(fi->level >= 0 && fi->level <= 3);
+        fsc = 0b001100 | fi->level;
         break;
     case ARMFault_Translation:
-        fsc = (fi->level & 3) | (0x1 << 2);
+        assert(fi->level >= -1 && fi->level <= 3);
+        if (fi->level < 0) {
+            fsc = 0b101011;
+        } else {
+            fsc = 0b000100 | fi->level;
+        }
         break;
     case ARMFault_SyncExternal:
         fsc = 0x10 | (fi->ea << 12);
         break;
     case ARMFault_SyncExternalOnWalk:
-        fsc = (fi->level & 3) | (0x5 << 2) | (fi->ea << 12);
+        assert(fi->level >= -1 && fi->level <= 3);
+        if (fi->level < 0) {
+            fsc = 0b010011;
+        } else {
+            fsc = 0b010100 | fi->level;
+        }
+        fsc |= fi->ea << 12;
         break;
     case ARMFault_SyncParity:
         fsc = 0x18;
         break;
     case ARMFault_SyncParityOnWalk:
-        fsc = (fi->level & 3) | (0x7 << 2);
+        assert(fi->level >= -1 && fi->level <= 3);
+        if (fi->level < 0) {
+            fsc = 0b011011;
+        } else {
+            fsc = 0b011100 | fi->level;
+        }
         break;
     case ARMFault_AsyncParity:
         fsc = 0x19;