diff --git a/PLASMA-SYS2.PO b/PLASMA-SYS2.PO
index c3295a7..58a0af1 100755
Binary files a/PLASMA-SYS2.PO and b/PLASMA-SYS2.PO differ
diff --git a/src/libsrc/apple/jit16.pla b/src/libsrc/apple/jit16.pla
index 37e7ce1..ad443d9 100644
--- a/src/libsrc/apple/jit16.pla
+++ b/src/libsrc/apple/jit16.pla
@@ -37,6 +37,12 @@ def defcpy(dst, defptr)#0
     *$0042   = dst
     call($C311, 0, 0, 0, $04) // CALL XMOVE with carry clear (AUX->MAIN) and ints disabled
 end
+//
+// Identify hardware addresses for certain byte sized access operations
+//
+def is_hwaddr(addr)
+    return addr >= $C000 and addr < $C100
+end
 include "libsrc/jit16core.pla"
 //
 // Install JIT compiler
diff --git a/src/libsrc/jit16core.pla b/src/libsrc/jit16core.pla
index 39de7be..4b87a8e 100644
--- a/src/libsrc/jit16core.pla
+++ b/src/libsrc/jit16core.pla
@@ -671,13 +671,24 @@ def compiler(defptr)#0
                     if A_IS_TOS
                         ^codeptr = $48; codeptr++ // PHA
                     fin
-                    codeptr=>0 = $20E2            // SEP #$20 -> 8 BIT ACCUM/MEM
-                    codeptr->2 = $AD              // LDA abs
-                    codeptr=>3 = dest
-                    codeptr=>5 = $20C2            // REP #$20 -> 16 BIT ACCUM/MEM
-                    codeptr->7 = $29              // AND #$00FF
-                    codeptr=>8 = $00FF
-                    codeptr    = codeptr + 10
+                    if is_hwaddr(dest)
+                        //
+                        // Ensure we only do byte sized accesses to H/W
+                        //
+                        codeptr=>0 = $20E2            // SEP #$20 -> 8 BIT ACCUM/MEM
+                        codeptr->2 = $AD              // LDA abs
+                        codeptr=>3 = dest
+                        codeptr=>5 = $20C2            // REP #$20 -> 16 BIT ACCUM/MEM
+                        codeptr->7 = $29              // AND #$00FF
+                        codeptr=>8 = $00FF
+                        codeptr    = codeptr + 10
+                    else
+                        codeptr->0 = $AD              // LDA abs
+                        codeptr=>1 = dest
+                        codeptr->3 = $29              // AND #$00FF
+                        codeptr=>4 = $00FF
+                        codeptr    = codeptr + 6
+                    fin
                     A_IS_TOS   = TRUE             // PHA
                     break
                 is $6A // LAW
@@ -1163,16 +1174,30 @@ def compiler(defptr)#0
                     if not A_IS_TOS
                         ^codeptr = $68; codeptr++ // PLA
                     fin
-                    codeptr=>0  = $E785           // STA TMP
-                    codeptr=>2  = $20E2           // SEP #$20 -> 8 BIT ACCUM/MEM
-                    codeptr->4  = $AD             // LDA abs
-                    codeptr=>5  = dest
-                    codeptr=>7  = $20C2           // REP #$20 -> 16 BIT ACCUM/MEM
-                    codeptr->9  = $29             // AND #$00FF
-                    codeptr=>10 = $00FF
-                    codeptr->12 = $18             // CLC
-                    codeptr=>13 = $E765           // ADC TMP
-                    codeptr     = codeptr + 15
+                    if is_hwaddr(dest)
+                        //
+                        // Ensure only byte sized accesses to H/W addresses
+                        //
+                        codeptr=>0  = $E785       // STA TMP
+                        codeptr=>2  = $20E2       // SEP #$20 -> 8 BIT ACCUM/MEM
+                        codeptr->4  = $AD         // LDA abs
+                        codeptr=>5  = dest
+                        codeptr=>7  = $20C2       // REP #$20 -> 16 BIT ACCUM/MEM
+                        codeptr->9  = $29         // AND #$00FF
+                        codeptr=>10 = $00FF
+                        codeptr->12 = $18         // CLC
+                        codeptr=>13 = $E765       // ADC TMP
+                        codeptr     = codeptr + 15
+                    else
+                        codeptr=>0 = $E785        // STA TMP
+                        codeptr->2 = $AD          // LDA abs
+                        codeptr=>3 = dest
+                        codeptr->5 = $29          // AND #$00FF
+                        codeptr=>6 = $00FF
+                        codeptr->8 = $18          // CLC
+                        codeptr=>9 = $E765        // ADC TMP
+                        codeptr     = codeptr + 15
+                    fin
                     A_IS_TOS    = TRUE            // PHA
                     break
                 is $B6 // ADDAW
@@ -1233,15 +1258,28 @@ def compiler(defptr)#0
                     if not A_IS_TOS
                         ^codeptr = $68; codeptr++ // PLA
                     fin
-                    codeptr=>0  = $E785           // STA TMP
-                    codeptr=>2  = $20E2           // SEP #$20 -> 8 BIT ACCUM/MEM
-                    codeptr->4  = $AD             // LDA abs
-                    codeptr=>5  = dest
-                    codeptr=>7  = $20C2           // REP #$20 -> 16 BIT ACCUM/MEM
-                    codeptr->9  = $29             // AND #$00FF
-                    codeptr=>10 = $00FF
-                    codeptr->12 = $0A             // ASL
-                    codeptr=>13 = $E765           // ADC TMP
+                    if is_hwaddr(dest)
+                        //
+                        // Ensure only byte sized accesses to H/W addresses
+                        //
+                        codeptr=>0  = $E785       // STA TMP
+                        codeptr=>2  = $20E2       // SEP #$20 -> 8 BIT ACCUM/MEM
+                        codeptr->4  = $AD         // LDA abs
+                        codeptr=>5  = dest
+                        codeptr=>7  = $20C2       // REP #$20 -> 16 BIT ACCUM/MEM
+                        codeptr->9  = $29         // AND #$00FF
+                        codeptr=>10 = $00FF
+                        codeptr->12 = $0A         // ASL
+                        codeptr=>13 = $E765       // ADC TMP
+                    else
+                        codeptr=>0  = $E785       // STA TMP
+                        codeptr->4  = $AD         // LDA abs
+                        codeptr=>5  = dest
+                        codeptr->9  = $29         // AND #$00FF
+                        codeptr=>10 = $00FF
+                        codeptr->12 = $0A         // ASL
+                        codeptr=>13 = $E765       // ADC TMP
+                    fin
                     codeptr     = codeptr + 15
                     A_IS_TOS    = TRUE            // PHA
                     break