diff --git a/extmod/moduzlib.c b/extmod/moduzlib.c
index f70ecd92c..253deac1e 100644
--- a/extmod/moduzlib.c
+++ b/extmod/moduzlib.c
@@ -35,6 +35,7 @@
 
 #if MICROPY_PY_UZLIB
 
+#define UZLIB_CONF_PARANOID_CHECKS (1)
 #include "../../lib/uzlib/src/tinf.h"
 
 #if 0 // print debugging info
@@ -50,7 +51,7 @@ typedef struct _mp_obj_decompio_t {
     bool eof;
 } mp_obj_decompio_t;
 
-STATIC unsigned char read_src_stream(TINF_DATA *data) {
+STATIC int read_src_stream(TINF_DATA *data) {
     byte *p = (void*)data;
     p -= offsetof(mp_obj_decompio_t, decomp);
     mp_obj_decompio_t *self = (mp_obj_decompio_t*)p;
@@ -112,7 +113,7 @@ STATIC mp_uint_t decompio_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *er
     }
 
     o->decomp.dest = buf;
-    o->decomp.destSize = size;
+    o->decomp.dest_limit = (unsigned char*)buf+size;
     int st = uzlib_uncompress_chksum(&o->decomp);
     if (st == TINF_DONE) {
         o->eof = true;
@@ -157,10 +158,10 @@ STATIC mp_obj_t mod_uzlib_decompress(size_t n_args, const mp_obj_t *args) {
     byte *dest_buf = m_new(byte, dest_buf_size);
 
     decomp->dest = dest_buf;
-    decomp->destSize = dest_buf_size;
+    decomp->dest_limit = dest_buf+dest_buf_size;
     DEBUG_printf("uzlib: Initial out buffer: " UINT_FMT " bytes\n", decomp->destSize);
     decomp->source = bufinfo.buf;
-
+    decomp->source_limit = (unsigned char *)bufinfo.buf + bufinfo.len;
     int st;
     bool is_zlib = true;
 
@@ -187,7 +188,7 @@ STATIC mp_obj_t mod_uzlib_decompress(size_t n_args, const mp_obj_t *args) {
         dest_buf = m_renew(byte, dest_buf, dest_buf_size, dest_buf_size + 256);
         dest_buf_size += 256;
         decomp->dest = dest_buf + offset;
-        decomp->destSize = 256;
+        decomp->dest_limit = dest_buf + offset + 256;
     }
 
     mp_uint_t final_sz = decomp->dest - dest_buf;
@@ -218,6 +219,7 @@ const mp_obj_module_t mp_module_uzlib = {
 // Source files #include'd here to make sure they're compiled in
 // only if module is enabled by config setting.
 
+#pragma GCC diagnostic ignored "-Wsign-compare"
 #include "../../lib/uzlib/src/tinflate.c"
 #include "../../lib/uzlib/src/tinfzlib.c"
 #include "../../lib/uzlib/src/tinfgzip.c"
diff --git a/lib/uzlib b/lib/uzlib
index 27176508e..f966da0fa 160000
--- a/lib/uzlib
+++ b/lib/uzlib
@@ -1 +1 @@
-Subproject commit 27176508e188c0900877e810be34198cd88dcb63
+Subproject commit f966da0fab121e910ea74f037f074538a2e6dbbb