diff --git a/kk_ihex.h b/kk_ihex.h
index 589f010..79119fe 100644
--- a/kk_ihex.h
+++ b/kk_ihex.h
@@ -106,7 +106,7 @@
 #ifndef KK_IHEX_H
 #define KK_IHEX_H
 
-#define KK_IHEX_VERSION "2015-02-26"
+#define KK_IHEX_VERSION "2015-03-04"
 
 #include <stdint.h>
 
diff --git a/kk_ihex_read.c b/kk_ihex_read.c
index 9e85064..cc372b0 100644
--- a/kk_ihex_read.c
+++ b/kk_ihex_read.c
@@ -90,7 +90,7 @@ ihex_end_read (struct ihex_state * const ihex) {
 }
 
 void
-ihex_read_byte (struct ihex_state * const ihex, const int byte) {
+ihex_read_byte (struct ihex_state * const ihex, const char byte) {
     uint_fast8_t b = (uint_fast8_t) byte;
     uint_fast8_t len = ihex->length;
     uint_fast8_t state = (ihex->flags & IHEX_READ_STATE_MASK);
@@ -169,7 +169,7 @@ save_read_state:
 
 void
 ihex_read_bytes (struct ihex_state * restrict ihex,
-                 char * restrict data,
+                 const char * restrict data,
                  ihex_count_t count) {
     while (count > 0) {
         ihex_read_byte(ihex, *data++);
diff --git a/kk_ihex_read.h b/kk_ihex_read.h
index d1f592b..295899b 100644
--- a/kk_ihex_read.h
+++ b/kk_ihex_read.h
@@ -1,5 +1,5 @@
 /*
- * kk_ihex_read.h: A simple library for reaing Intel HEX data. See
+ * kk_ihex_read.h: A simple library for reading Intel HEX data. See
  * the accompanying kk_ihex_write.h for IHEX write support.
  *
  *
@@ -53,11 +53,12 @@ void ihex_begin_read(struct ihex_state *ihex);
 void ihex_read_at_address(struct ihex_state *ihex,
                           ihex_address_t address);
 
-// Read a single byte
-void ihex_read_byte(struct ihex_state *ihex, int chr);
+// Read a single character
+void ihex_read_byte(struct ihex_state *ihex, char chr);
 
 // Read `count` bytes from `data`
-void ihex_read_bytes(struct ihex_state * restrict ihex, char * restrict data,
+void ihex_read_bytes(struct ihex_state * restrict ihex,
+                     const char * restrict data,
                      ihex_count_t count);
 
 // End reading (may call `ihex_data_read` if there is data waiting)
diff --git a/kk_ihex_write.c b/kk_ihex_write.c
index eaa1973..5df56de 100644
--- a/kk_ihex_write.c
+++ b/kk_ihex_write.c
@@ -213,7 +213,7 @@ ihex_write_byte (struct ihex_state * const ihex, uint8_t byte) {
 
 void
 ihex_write_bytes (struct ihex_state * restrict const ihex,
-                  uint8_t * restrict r,
+                  const uint8_t * restrict r,
                   ihex_count_t count) {
     while (count > 0) {
         if (ihex->line_length > ihex->length) {
diff --git a/kk_ihex_write.h b/kk_ihex_write.h
index 9ba69ea..de6e101 100644
--- a/kk_ihex_write.h
+++ b/kk_ihex_write.h
@@ -116,7 +116,7 @@ void ihex_write_byte(struct ihex_state *ihex, uint8_t b);
 
 // Write `count` bytes from `data`
 void ihex_write_bytes(struct ihex_state * restrict ihex,
-                      uint8_t * restrict data,
+                      const uint8_t * restrict data,
                       ihex_count_t count);
 
 // End writing (flush buffers, write end of file record)