diff --git a/src/lib/formats/apridisk.cpp b/src/lib/formats/apridisk.cpp
index dd444b9245d..a42aa9fa4d4 100644
--- a/src/lib/formats/apridisk.cpp
+++ b/src/lib/formats/apridisk.cpp
@@ -60,7 +60,7 @@ bool apridisk_format::load(io_generic *io, uint32_t form_factor, floppy_image *i
 		uint8_t sector_header[16];
 		io_generic_read(io, sector_header, file_offset, 16);
 
-		int32_t type = pick_integer_le(&sector_header, 0, 4);
+		uint32_t type = pick_integer_le(&sector_header, 0, 4);
 		uint16_t compression = pick_integer_le(&sector_header, 4, 2);
 		uint16_t header_size = pick_integer_le(&sector_header, 6, 2);
 		uint32_t data_size = pick_integer_le(&sector_header, 8, 4);
diff --git a/src/lib/formats/apridisk.h b/src/lib/formats/apridisk.h
index 81db4b41105..1155a0b4a9a 100644
--- a/src/lib/formats/apridisk.h
+++ b/src/lib/formats/apridisk.h
@@ -33,7 +33,7 @@ private:
 	static const int APR_HEADER_SIZE = 128;
 
 	// sector types
-	enum
+	enum : uint32_t
 	{
 		APR_DELETED = 0xe31d0000,
 		APR_SECTOR  = 0xe31d0001,