diff --git a/src/ethosu_device.c b/src/ethosu_device.c
index 4729c49..ba7e0d5 100644
--- a/src/ethosu_device.c
+++ b/src/ethosu_device.c
@@ -100,7 +100,7 @@
 #if !defined(ARM_NPU_STUB)
     ASSERT(num_base_addr <= ETHOSU_DRIVER_BASEP_INDEXES);
 
-    uint64_t qbase = (uint64_t)cmd_stream_ptr + BASE_POINTER_OFFSET;
+    uint64_t qbase = (uintptr_t)cmd_stream_ptr + BASE_POINTER_OFFSET;
     ASSERT(qbase <= ADDRESS_MASK);
     LOG_DEBUG("QBASE=0x%016llx, QSIZE=%u, base_pointer_offset=0x%08x\n", qbase, cms_length, BASE_POINTER_OFFSET);
     ethosu_write_reg(dev, NPU_REG_QBASE0, qbase & 0xffffffff);
diff --git a/src/ethosu_driver.c b/src/ethosu_driver.c
index a5f0bfe..c640f25 100644
--- a/src/ethosu_driver.c
+++ b/src/ethosu_driver.c
@@ -235,7 +235,7 @@
              fast_memory,
              fast_memory_size);
 
-    ethosu_drv.fast_memory      = (uint64_t)fast_memory;
+    ethosu_drv.fast_memory      = (uint32_t)fast_memory;
     ethosu_drv.fast_memory_size = fast_memory_size;
 
     if (ETHOSU_SUCCESS != ethosu_dev_init(&ethosu_drv.dev, base_address))