diff --git a/lib/scheme/bytevector-test.sld b/lib/scheme/bytevector-test.sld
index c26417e7..a8192ddb 100644
--- a/lib/scheme/bytevector-test.sld
+++ b/lib/scheme/bytevector-test.sld
@@ -234,11 +234,18 @@
                (equal? (bytevector-s16-native-ref b 0)
                        (- 44444 65536)))))
 
-      (test-assert "bytevector-s16-{ref,set!} [unaligned]"
-        (let ((b (make-bytevector 3)))
+      (test-assert "bytevector-{u16,s16}-{ref,set!} [unaligned]"
+        (let ((b (make-bytevector 5)))
           (bytevector-s16-set! b 1 -77 (endianness little))
-          (equal? (bytevector-s16-ref b 1 (endianness little))
-                  -77)))
+          (bytevector-s16-set! b 3 -77 (endianness big))
+          (and (equal? (bytevector-s16-ref b 1 (endianness little))
+                       -77)
+               (equal? (bytevector-u16-ref b 1 (endianness little))
+                       (- 65536 77))
+               (equal? (bytevector-s16-ref b 3 (endianness big))
+                       -77)
+               (equal? (bytevector-u16-ref b 3 (endianness big))
+                       (- 65536 77)))))
       (test-end)
 
       (test-begin "2.6 Operations on 32-bit Integers")
@@ -276,6 +283,19 @@
                        2222222222)
                (equal? (bytevector-s32-native-ref b 0)
                        (- 2222222222 (expt 2 32))))))
+
+      (test-assert "bytevector-{u32,s32}-{ref,set!} [unaligned]"
+        (let ((b (make-bytevector 9)))
+          (bytevector-s32-set! b 1 -77777 (endianness little))
+          (bytevector-s32-set! b 5 -77777 (endianness big))
+          (and (equal? (bytevector-s32-ref b 1 (endianness little))
+                       -77777)
+               (equal? (bytevector-u32-ref b 1 (endianness little))
+                       (- (expt 2 32) 77777))
+               (equal? (bytevector-s32-ref b 5 (endianness big))
+                       -77777)
+               (equal? (bytevector-u32-ref b 5 (endianness big))
+                       (- (expt 2 32) 77777)))))
       (test-end)
 
       (test-begin "2.7 Operations on 64-bit Integers")
@@ -314,6 +334,18 @@
           (bytevector-u64-set! b 0  0 (endianness big))
           (= 0 (bytevector-u64-ref b 0 (endianness big)))))
 
+      (test-assert "bytevector-{u64,s64}-{ref,set!} [unaligned]"
+        (let ((b (make-bytevector 17)))
+          (bytevector-s64-set! b 1 -7777777777 (endianness little))
+          (bytevector-s64-set! b 9 -7777777777 (endianness big))
+          (and (equal? (bytevector-s64-ref b 1 (endianness little))
+                       -7777777777)
+               (equal? (bytevector-u64-ref b 1 (endianness little))
+                       (- (expt 2 64) 7777777777))
+               (equal? (bytevector-s64-ref b 9 (endianness big))
+                       -7777777777)
+               (equal? (bytevector-u64-ref b 9 (endianness big))
+                       (- (expt 2 64) 7777777777)))))
       (test-end)
 
       (test-begin "2.8 Operations on IEEE-754 Representations")
@@ -375,6 +407,14 @@
           (bytevector-ieee-double-set! b 8 number (endianness big))
           (equal? (bytevector-ieee-double-ref b 0 (endianness little))
                   (bytevector-ieee-double-ref b 8 (endianness big)))))
+
+      (test-assert "bytevector-ieee-double-{ref,set!} [unaligned]"
+        (let ((b (make-bytevector 17))
+              (number 3.14))
+          (bytevector-ieee-double-set! b 1 number (endianness little))
+          (bytevector-ieee-double-set! b 9 number (endianness big))
+          (equal? (bytevector-ieee-double-ref b 1 (endianness little))
+                  (bytevector-ieee-double-ref b 9 (endianness big)))))
       (test-end)
 
 
diff --git a/lib/scheme/bytevector.stub b/lib/scheme/bytevector.stub
index 88c6acb7..7698c523 100644
--- a/lib/scheme/bytevector.stub
+++ b/lib/scheme/bytevector.stub
@@ -50,6 +50,76 @@ static double sexp_swap_double(const double x) {
   return y;
 }
 
+/* 16-bit integers */
+static inline int16_t ref_s16(const void* p) {
+  int16_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline uint16_t ref_u16(const void* p) {
+  uint16_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline void set_s16(void* p, int16_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+static inline void set_u16(void* p, uint16_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+/* 32-bit integers */
+static inline int32_t ref_s32(const void* p) {
+  int32_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline uint32_t ref_u32(const void* p) {
+  uint32_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline void set_s32(void* p, int32_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+static inline void set_u32(void* p, uint32_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+/* 64-bit integers */
+static inline int64_t ref_s64(const void* p) {
+  int64_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline uint64_t ref_u64(const void* p) {
+  uint64_t v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline void set_s64(void* p, int64_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+static inline void set_u64(void* p, uint64_t v) {
+  memcpy(p, &v, sizeof(v));
+}
+/* 32-bit floats */
+static inline float ref_f32(const void* p) {
+  float v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline void set_f32(void* p, float v) {
+  memcpy(p, &v, sizeof(v));
+}
+/* 64-bit floats */
+static inline double ref_f64(const void* p) {
+  double v;
+  memcpy(&v, p, sizeof(v));
+  return v;
+}
+static inline void set_f64(void* p, double v) {
+  memcpy(p, &v, sizeof(v));
+}
+
 sexp_sint_t decode_utf8(unsigned char* p, int ch_len) {
   if (ch_len <= 1)
     return *p;
@@ -222,101 +292,101 @@ sexp utf32_2_str(sexp ctx, char* bv, int len, sexp endianness, int endianness_ma
   (inline "((int8_t*)arg0)[arg1] = arg2"))
 
 (define-c int16_t bytevector-s16-native-ref (bytevector int)
-  (inline "*((int16_t*)(arg0+arg1))"))
+  (inline "ref_s16(arg0+arg1)"))
 (define-c void bytevector-s16-native-set! (bytevector int int16_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((int16_t*)(arg0+arg1)) = arg2"))
+  (inline "set_s16(arg0+arg1, arg2)"))
 
 (define-c int16_t bytevector-s16-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((int16_t*)(arg1+arg2)) : sexp_swap_s16(*((int16_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_s16(arg1+arg2) : sexp_swap_s16(ref_s16(arg1+arg2)))"))
 (define-c void bytevector-s16-set! ((value ctx sexp) bytevector int int16_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((int16_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s16(arg3))"))
+  (inline "set_s16(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s16(arg3)))"))
 
 (define-c int32_t bytevector-s32-native-ref (bytevector int)
-  (inline "*((int32_t*)(arg0+arg1))"))
+  (inline "ref_s32(arg0+arg1)"))
 (define-c void bytevector-s32-native-set! (bytevector int int32_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((int32_t*)(arg0+arg1)) = arg2"))
+  (inline "set_s32(arg0+arg1, arg2)"))
 
 (define-c int32_t bytevector-s32-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((int32_t*)(arg1+arg2)) : sexp_swap_s32(*((int32_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_s32(arg1+arg2) : sexp_swap_s32(ref_s32(arg1+arg2)))"))
 (define-c void bytevector-s32-set! ((value ctx sexp) bytevector int int32_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((int32_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s32(arg3))"))
+  (inline "set_s32(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s32(arg3)))"))
 
 (define-c int64_t bytevector-s64-native-ref (bytevector int)
-  (inline "*((int64_t*)(arg0+arg1))"))
+  (inline "ref_s64(arg0+arg1)"))
 (define-c void bytevector-s64-native-set! (bytevector int int64_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((int64_t*)(arg0+arg1)) = arg2"))
+  (inline "set_s64(arg0+arg1, arg2)"))
 
 (define-c int64_t bytevector-s64-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((int64_t*)(arg1+arg2)) : sexp_swap_s64(*((int64_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_s64(arg1+arg2) : sexp_swap_s64(ref_s64(arg1+arg2)))"))
 (define-c void bytevector-s64-set! ((value ctx sexp) bytevector int int64_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((int64_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s64(arg3))"))
+  (inline "set_s64(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_s64(arg3)))"))
 
 (define-c uint16_t bytevector-u16-native-ref (bytevector int)
-  (inline "*((uint16_t*)(arg0+arg1))"))
+  (inline "ref_u16(arg0+arg1)"))
 (define-c void bytevector-u16-native-set! (bytevector int uint16_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((uint16_t*)(arg0+arg1)) = arg2"))
+  (inline "set_u16(arg0+arg1, arg2)"))
 
 (define-c uint16_t bytevector-u16-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((uint16_t*)(arg1+arg2)) : sexp_swap_u16(*((uint16_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_u16(arg1+arg2) : sexp_swap_u16(ref_u16(arg1+arg2)))"))
 (define-c void bytevector-u16-set! ((value ctx sexp) bytevector int uint16_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((uint16_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u16(arg3))"))
+  (inline "set_u16(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u16(arg3)))"))
 
 (define-c uint32_t bytevector-u32-native-ref (bytevector int)
-  (inline "*((uint32_t*)(arg0+arg1))"))
+  (inline "ref_u32(arg0+arg1)"))
 (define-c void bytevector-u32-native-set! (bytevector int uint32_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((uint32_t*)(arg0+arg1)) = arg2"))
+  (inline "set_u32(arg0+arg1, arg2)"))
 
 (define-c uint32_t bytevector-u32-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((uint32_t*)(arg1+arg2)) : sexp_swap_u32(*((uint32_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_u32(arg1+arg2) : sexp_swap_u32(ref_u32(arg1+arg2)))"))
 (define-c void bytevector-u32-set! ((value ctx sexp) bytevector int uint32_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((uint32_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u32(arg3))"))
+  (inline "set_u32(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u32(arg3)))"))
 
 (define-c uint64_t bytevector-u64-native-ref (bytevector int)
-  (inline "*((uint64_t*)(arg0+arg1))"))
+  (inline "ref_u64(arg0+arg1)"))
 (define-c void bytevector-u64-native-set! (bytevector int uint64_t)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((uint64_t*)(arg0+arg1)) = arg2"))
+  (inline "set_u64(arg0+arg1, arg2)"))
 
 (define-c uint64_t bytevector-u64-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((uint64_t*)(arg1+arg2)) : sexp_swap_u64(*((uint64_t*)(arg1+arg2))))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_u64(arg1+arg2) : sexp_swap_u64(ref_u64(arg1+arg2)))"))
 (define-c void bytevector-u64-set! ((value ctx sexp) bytevector int uint64_t sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((uint64_t*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u64(arg3))"))
+  (inline "set_u64(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_u64(arg3)))"))
 
 
 (define-c float bytevector-ieee-single-native-ref (bytevector int)
-  (inline "*((float*)(arg0+arg1))"))
+  (inline "ref_f32(arg0+arg1)"))
 (define-c void bytevector-ieee-single-native-set! (bytevector int float)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((float*)(arg0+arg1)) = arg2"))
+  (inline "set_f32(arg0+arg1, arg2)"))
 
 (define-c float bytevector-ieee-single-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((float*)(arg1+arg2)) : sexp_swap_float(*(float*)(arg1+arg2)))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_f32(arg1+arg2) : sexp_swap_float(ref_f32(arg1+arg2)))"))
 (define-c void bytevector-ieee-single-set! ((value ctx sexp) bytevector int float sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((float*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_float(arg3))"))
+  (inline "set_f32(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_float(arg3)))"))
 
 (define-c double bytevector-ieee-double-native-ref (bytevector int)
-  (inline "*((double*)(arg0+arg1))"))
+  (inline "ref_f64(arg0+arg1)"))
 (define-c void bytevector-ieee-double-native-set! (bytevector int double)
   (assert (< -1 arg1 (bytevector-length arg0)))
-  (inline "*((double*)(arg0+arg1)) = arg2"))
+  (inline "set_f64(arg0+arg1, arg2)"))
 
 (define-c double bytevector-ieee-double-ref ((value ctx sexp) bytevector int sexp)
-  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? *((double*)(arg1+arg2)) : sexp_swap_double(*(double*)(arg1+arg2)))"))
+  (inline "(arg3 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? ref_f64(arg1+arg2) : sexp_swap_double(ref_f64(arg1+arg2)))"))
 (define-c void bytevector-ieee-double-set! ((value ctx sexp) bytevector int double sexp)
   (assert (< -1 arg2 (bytevector-length arg1)))
-  (inline "*((double*)(arg1+arg2)) = (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_double(arg3))"))
+  (inline "set_f64(arg1+arg2, (arg4 == sexp_global(arg0, SEXP_G_ENDIANNESS) ? arg3 : sexp_swap_double(arg3)))"))
 
 (define-c sexp (%string->utf16 "str2utf16")
   ((value ctx sexp) string (value (string-size arg1) int) (default (native-endianness) sexp)))