diff --git a/tests/extmod/uzlib_decompio_gz.py b/tests/extmod/uzlib_decompio_gz.py
index 5ab25354c..7572e9693 100644
--- a/tests/extmod/uzlib_decompio_gz.py
+++ b/tests/extmod/uzlib_decompio_gz.py
@@ -20,6 +20,16 @@ print(inp.read(1))
 print(inp.read())
 print(buf.seek(0, 1))
 
+# Check FHCRC field
+buf = io.BytesIO(b'\x1f\x8b\x08\x02\x99\x0c\xe5W\x00\x03\x00\x00\xcbH\xcd\xc9\xc9\x07\x00\x86\xa6\x106\x05\x00\x00\x00')
+inp = zlib.DecompIO(buf, 16 + 8)
+print(inp.read())
+
+# Check FEXTRA field
+buf = io.BytesIO(b'\x1f\x8b\x08\x04\x99\x0c\xe5W\x00\x03\x01\x00X\xcbH\xcd\xc9\xc9\x07\x00\x86\xa6\x106\x05\x00\x00\x00')
+inp = zlib.DecompIO(buf, 16 + 8)
+print(inp.read())
+
 # broken header
 buf = io.BytesIO(b'\x1f\x8c\x08\x08\x99\x0c\xe5W\x00\x03hello\x00\xcbH\xcd\xc9\xc9\x07\x00\x86\xa6\x106\x05\x00\x00\x00')
 try:
diff --git a/tests/extmod/uzlib_decompio_gz.py.exp b/tests/extmod/uzlib_decompio_gz.py.exp
index 2330580f8..20a30c82a 100644
--- a/tests/extmod/uzlib_decompio_gz.py.exp
+++ b/tests/extmod/uzlib_decompio_gz.py.exp
@@ -7,5 +7,7 @@ b'lo'
 b''
 b''
 31
+b'hello'
+b'hello'
 ValueError
 OSError(22,)