diff --git a/cmd/unzip.c b/cmd/unzip.c
index e7a3f9808b2..da958f12803 100644
--- a/cmd/unzip.c
+++ b/cmd/unzip.c
@@ -53,8 +53,8 @@ static int do_gzwrite(struct cmd_tbl *cmdtp, int flag,
 	unsigned char *addr;
 	unsigned long length;
 	unsigned long writebuf = 1<<20;
-	u64 startoffs = 0;
-	u64 szexpected = 0;
+	off_t startoffs = 0;
+	size_t szexpected = 0;
 
 	if (argc < 5)
 		return CMD_RET_USAGE;
diff --git a/include/gzip.h b/include/gzip.h
index 304002ffc42..fe8e21dc2a9 100644
--- a/include/gzip.h
+++ b/include/gzip.h
@@ -58,11 +58,11 @@ int zunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp,
  *	gzwrite_progress_finish called at end of loop to
  *		indicate success (retcode=0) or failure
  */
-void gzwrite_progress_init(ulong expected_size);
+void gzwrite_progress_init(size_t expected_size);
 
-void gzwrite_progress(int iteration, ulong bytes_written, ulong total_bytes);
+void gzwrite_progress(int iteration, ulong bytes_written, size_t total_bytes);
 
-void gzwrite_progress_finish(int retcode, ulong totalwritten, ulong totalsize,
+void gzwrite_progress_finish(int retcode, ulong totalwritten, size_t totalsize,
 			     u32 expected_crc, u32 calculated_crc);
 
 /**
@@ -77,8 +77,8 @@ void gzwrite_progress_finish(int retcode, ulong totalwritten, ulong totalsize,
  *		for files under 4GiB
  * Return: 0 if OK, -1 on error
  */
-int gzwrite(unsigned char *src, int len, struct blk_desc *dev, ulong szwritebuf,
-	    ulong startoffs, ulong szexpected);
+int gzwrite(unsigned char *src, size_t len, struct blk_desc *dev,
+	    size_t szwritebuf, off_t startoffs, size_t szexpected);
 
 /**
  * gzip()- Compress data into a buffer using the gzip algorithm
diff --git a/lib/gunzip.c b/lib/gunzip.c
index a05dcde9a75..76f3397fced 100644
--- a/lib/gunzip.c
+++ b/lib/gunzip.c
@@ -84,7 +84,7 @@ __rcode int gunzip(void *dst, int dstlen, unsigned char *src, unsigned long *len
 
 #ifdef CONFIG_CMD_UNZIP
 __weak
-void gzwrite_progress_init(ulong expectedsize)
+void gzwrite_progress_init(size_t expectedsize)
 {
 	putc('\n');
 }
@@ -92,35 +92,32 @@ void gzwrite_progress_init(ulong expectedsize)
 __weak
 void gzwrite_progress(int iteration,
 		     ulong bytes_written,
-		     ulong total_bytes)
+		     size_t total_bytes)
 {
 	if (0 == (iteration & 3))
-		printf("%lu/%lu\r", bytes_written, total_bytes);
+		printf("%lu/%zu\r", bytes_written, total_bytes);
 }
 
 __weak
 void gzwrite_progress_finish(int returnval,
 			     ulong bytes_written,
-			     ulong total_bytes,
+			     size_t total_bytes,
 			     u32 expected_crc,
 			     u32 calculated_crc)
 {
 	if (0 == returnval) {
-		printf("\n\t%lu bytes, crc 0x%08x\n",
+		printf("\n\t%zu bytes, crc 0x%08x\n",
 		       total_bytes, calculated_crc);
 	} else {
-		printf("\n\tuncompressed %lu of %lu\n"
+		printf("\n\tuncompressed %lu of %zu\n"
 		       "\tcrcs == 0x%08x/0x%08x\n",
 		       bytes_written, total_bytes,
 		       expected_crc, calculated_crc);
 	}
 }
 
-int gzwrite(unsigned char *src, int len,
-	    struct blk_desc *dev,
-	    unsigned long szwritebuf,
-	    ulong startoffs,
-	    ulong szexpected)
+int gzwrite(unsigned char *src, size_t len, struct blk_desc *dev,
+	    size_t szwritebuf, off_t startoffs, size_t szexpected)
 {
 	int i, flags;
 	z_stream s;
@@ -130,13 +127,18 @@ int gzwrite(unsigned char *src, int len,
 	ulong totalfilled = 0;
 	lbaint_t blksperbuf, outblock;
 	u32 expected_crc;
-	u32 payload_size;
+	size_t payload_size;
 	int iteration = 0;
 
+	if (len > 0xffffffff) {
+		log_err("Input size over 4 GiB in size not supported\n");
+		return -1;
+	}
+
 	if (!szwritebuf ||
 	    (szwritebuf % dev->blksz) ||
 	    (szwritebuf < dev->blksz)) {
-		printf("%s: size %lu not a multiple of %lu\n",
+		printf("%s: size %zu not a multiple of %lu\n",
 		       __func__, szwritebuf, dev->blksz);
 		return -1;
 	}
@@ -182,12 +184,12 @@ int gzwrite(unsigned char *src, int len,
 	if (szexpected == 0) {
 		szexpected = le32_to_cpu(szuncompressed);
 	} else if (szuncompressed != (u32)szexpected) {
-		printf("size of %lx doesn't match trailer low bits %x\n",
+		printf("size of %zx doesn't match trailer low bits %x\n",
 		       szexpected, szuncompressed);
 		return -1;
 	}
 	if (lldiv(szexpected, dev->blksz) > (dev->lba - outblock)) {
-		printf("%s: uncompressed size %lu exceeds device size\n",
+		printf("%s: uncompressed size %zu exceeds device size\n",
 		       __func__, szexpected);
 		return -1;
 	}