diff --git a/src/Adafruit_MCPSRAM.h b/src/Adafruit_MCPSRAM.h
index 529eb49..a39d98a 100644
--- a/src/Adafruit_MCPSRAM.h
+++ b/src/Adafruit_MCPSRAM.h
@@ -37,7 +37,7 @@ class Adafruit_MCPSRAM {
   void csLow();
 
 private:
-  boolean hwSPI; ///< true if using hardware SPI
+  bool hwSPI; ///< true if using hardware SPI
 #ifdef HAVE_PORTREG
   PortReg *mosiport, *clkport, *csport, *misoport;
   PortMask mosipinmask, clkpinmask, cspinmask, misopinmask;
diff --git a/src/drivers/Adafruit_ACeP.cpp b/src/drivers/Adafruit_ACeP.cpp
index 19f712e..d7acbb6 100644
--- a/src/drivers/Adafruit_ACeP.cpp
+++ b/src/drivers/Adafruit_ACeP.cpp
@@ -129,7 +129,7 @@ void Adafruit_ACEP::deGhost() {
   uint32_t remaining = (600UL * 448UL / 2);
   while (remaining) {
     uint8_t block[256];
-    uint32_t numbytes = min(remaining, sizeof(block));
+    uint32_t numbytes = min(remaining, (uint32_t)sizeof(block));
     memset(block, 0x77, numbytes);
     EPD_data(block, numbytes);
     remaining -= numbytes;
diff --git a/src/drivers/Adafruit_UC8151D.cpp b/src/drivers/Adafruit_UC8151D.cpp
index 3272c89..1014fc3 100644
--- a/src/drivers/Adafruit_UC8151D.cpp
+++ b/src/drivers/Adafruit_UC8151D.cpp
@@ -305,7 +305,7 @@ void Adafruit_UC8151D::displayPartial(uint16_t x1, uint16_t y1, uint16_t x2,
     uint32_t offset = 0;
     uint8_t mcp_buf[16];
     while (remaining) {
-      uint8_t to_xfer = min(sizeof(mcp_buf), remaining);
+      uint8_t to_xfer = min((uint32_t)sizeof(mcp_buf), remaining);
 
       sram.read(buffer2_addr + offset, mcp_buf, to_xfer);
       sram.write(buffer1_addr + offset, mcp_buf, to_xfer);