diff --git a/common/pimoroni_i2c.cpp b/common/pimoroni_i2c.cpp
index 16a61aea..887fa1b7 100644
--- a/common/pimoroni_i2c.cpp
+++ b/common/pimoroni_i2c.cpp
@@ -68,7 +68,7 @@ namespace pimoroni {
         return value;
     }
 
-    int I2C::write_bytes(uint8_t address, uint8_t reg, uint8_t *buf, int len) {
+    int I2C::write_bytes(uint8_t address, uint8_t reg, const uint8_t *buf, int len) {
         uint8_t buffer[len + 1];
         buffer[0] = reg;
         for(int x = 0; x < len; x++) {
diff --git a/common/pimoroni_i2c.hpp b/common/pimoroni_i2c.hpp
index 5066022a..6348acf4 100644
--- a/common/pimoroni_i2c.hpp
+++ b/common/pimoroni_i2c.hpp
@@ -55,7 +55,7 @@ namespace pimoroni {
         int16_t reg_read_int16(uint8_t address, uint8_t reg);
         uint32_t reg_read_uint32(uint8_t address, uint8_t reg);
 
-        int write_bytes(uint8_t address, uint8_t reg, uint8_t *buf, int len);
+        int write_bytes(uint8_t address, uint8_t reg, const uint8_t *buf, int len);
         int read_bytes(uint8_t address, uint8_t reg, uint8_t *buf, int len);
         uint8_t get_bits(uint8_t address, uint8_t reg, uint8_t shift, uint8_t mask=0b1);
         void set_bits(uint8_t address, uint8_t reg, uint8_t shift, uint8_t mask=0b1);
diff --git a/drivers/is31fl3731/is31fl3731.cpp b/drivers/is31fl3731/is31fl3731.cpp
index 334407d8..7a68ec6e 100644
--- a/drivers/is31fl3731/is31fl3731.cpp
+++ b/drivers/is31fl3731/is31fl3731.cpp
@@ -77,14 +77,7 @@ namespace pimoroni {
 
   void IS31FL3731::enable(std::initializer_list<uint8_t> pattern, uint8_t frame) {
     i2c->reg_write_uint8(address, reg::BANK, frame);
-    uint8_t enable_buf[19];
-    enable_buf[0] = ENABLE_OFFSET;
-    uint8_t offset = 1;
-    for(auto byte : pattern) {
-      enable_buf[offset] = byte;
-      offset++;
-    }
-    i2c->write_blocking(address, enable_buf, sizeof(enable_buf), false);
+    i2c->write_bytes(address, ENABLE_OFFSET, pattern.begin(), pattern.size());
   }
 
   void IS31FL3731::set(uint8_t index, uint8_t brightness) {