diff --git a/Adafruit_BusIO_Register.cpp b/Adafruit_BusIO_Register.cpp
index f3e8187..7fc555f 100644
--- a/Adafruit_BusIO_Register.cpp
+++ b/Adafruit_BusIO_Register.cpp
@@ -111,11 +111,12 @@ Adafruit_BusIO_Register::Adafruit_BusIO_Register(
 /*!
  *    @brief  Write a buffer of data to the register location
  *    @param  buffer Pointer to data to write
- *    @param  len Number of bytes to write
+ *    @param  len Number of bytes to write - don't exceed maxbuffersize()
+ * which may be as small as 32 bytes
  *    @return True on successful write (only really useful for I2C as SPI is
  * uncheckable)
  */
-bool Adafruit_BusIO_Register::write(uint8_t *buffer, uint8_t len) {
+bool Adafruit_BusIO_Register::write(uint8_t *buffer, size_t len) {
   uint8_t addrbuffer[2] = {(uint8_t)(_address & 0xFF),
                            (uint8_t)(_address >> 8)};
   if (_i2cdevice) {
@@ -216,7 +217,7 @@ uint32_t Adafruit_BusIO_Register::readCached(void) { return _cached; }
    @param len Number of bytes to read into the buffer
    @return true on successful read, otherwise false
 */
-bool Adafruit_BusIO_Register::read(uint8_t *buffer, uint8_t len) {
+bool Adafruit_BusIO_Register::read(uint8_t *buffer, size_t len) {
   uint8_t addrbuffer[2] = {(uint8_t)(_address & 0xFF),
                            (uint8_t)(_address >> 8)};
   if (_i2cdevice) {
diff --git a/Adafruit_BusIO_Register.h b/Adafruit_BusIO_Register.h
index 046e04c..d733f82 100644
--- a/Adafruit_BusIO_Register.h
+++ b/Adafruit_BusIO_Register.h
@@ -63,12 +63,12 @@ class Adafruit_BusIO_Register {
                           uint8_t byteorder = LSBFIRST,
                           uint8_t address_width = 1);
 
-  bool read(uint8_t *buffer, uint8_t len);
+  bool read(uint8_t *buffer, size_t len);
   bool read(uint8_t *value);
   bool read(uint16_t *value);
   uint32_t read(void);
   uint32_t readCached(void);
-  bool write(uint8_t *buffer, uint8_t len);
+  bool write(uint8_t *buffer, size_t len);
   bool write(uint32_t value, uint8_t numbytes = 0);
 
   uint8_t width(void);
diff --git a/Adafruit_I2CDevice.cpp b/Adafruit_I2CDevice.cpp
index 2633cf1..1f7e545 100644
--- a/Adafruit_I2CDevice.cpp
+++ b/Adafruit_I2CDevice.cpp
@@ -15,6 +15,8 @@ Adafruit_I2CDevice::Adafruit_I2CDevice(uint8_t addr, TwoWire *theWire) {
   _maxBufferSize = 250; // as defined in Wire.h's RingBuffer
 #elif defined(ESP32)
   _maxBufferSize = I2C_BUFFER_LENGTH;
+#elif defined(TwoWireKinetis_h) || defined(TwoWireIMXRT_h) // Teensy 3.x || 4.x
+  _maxBufferSize = BUFFER_LENGTH;
 #else
   _maxBufferSize = 32;
 #endif
@@ -174,7 +176,7 @@ bool Adafruit_I2CDevice::write(const uint8_t *buffer, size_t len, bool stop,
 
 /*!
  *    @brief  Read from I2C into a buffer from the I2C device.
- *    Cannot be more than maxBufferSize() bytes.
+ *    Unlimited length, in chunks of maxBufferSize() bytes.
  *    @param  buffer Pointer to buffer of data to read into
  *    @param  len Number of bytes from buffer to read.
  *    @param  stop Whether to send an I2C STOP signal on read
@@ -235,8 +237,8 @@ bool Adafruit_I2CDevice::_read(uint8_t *buffer, size_t len, bool stop) {
 
 /*!
  *    @brief  Write some data, then read some data from I2C into another buffer.
- *    Cannot be more than maxBufferSize() bytes. The buffers can point to
- *    same/overlapping locations.
+ *    Written buffer cannot be more than maxBufferSize() bytes. The buffers
+ *    can point to same/overlapping locations.
  *    @param  write_buffer Pointer to buffer of data to write from
  *    @param  write_len Number of bytes from buffer to write.
  *    @param  read_buffer Pointer to buffer of data to read into.
diff --git a/library.properties b/library.properties
index 1615468..85f8c14 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=Adafruit BusIO
-version=1.17.4
+version=1.17.5
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=This is a library for abstracting away UART, I2C and SPI interfacing