diff --git a/extmod/uzlib/adler32.c b/extmod/uzlib/adler32.c
index f99b2d7f40..b06a7b37cc 100644
--- a/extmod/uzlib/adler32.c
+++ b/extmod/uzlib/adler32.c
@@ -41,12 +41,12 @@
 #define A32_BASE 65521
 #define A32_NMAX 5552
 
-unsigned int tinf_adler32(const void *data, unsigned int length)
+unsigned int uzlib_adler32(const void *data, unsigned int length, unsigned int prev_sum /* 1 */)
 {
    const unsigned char *buf = (const unsigned char *)data;
 
-   unsigned int s1 = 1;
-   unsigned int s2 = 0;
+   unsigned int s1 = prev_sum & 0xffff;
+   unsigned int s2 = prev_sum >> 16;
 
    while (length > 0)
    {
diff --git a/extmod/uzlib/crc32.c b/extmod/uzlib/crc32.c
new file mode 100644
index 0000000000..8c9976594d
--- /dev/null
+++ b/extmod/uzlib/crc32.c
@@ -0,0 +1,63 @@
+/*
+ * CRC32 checksum
+ *
+ * Copyright (c) 1998-2003 by Joergen Ibsen / Jibz
+ * All Rights Reserved
+ *
+ * http://www.ibsensoftware.com/
+ *
+ * This software is provided 'as-is', without any express
+ * or implied warranty.  In no event will the authors be
+ * held liable for any damages arising from the use of
+ * this software.
+ *
+ * Permission is granted to anyone to use this software
+ * for any purpose, including commercial applications,
+ * and to alter it and redistribute it freely, subject to
+ * the following restrictions:
+ *
+ * 1. The origin of this software must not be
+ *    misrepresented; you must not claim that you
+ *    wrote the original software. If you use this
+ *    software in a product, an acknowledgment in
+ *    the product documentation would be appreciated
+ *    but is not required.
+ *
+ * 2. Altered source versions must be plainly marked
+ *    as such, and must not be misrepresented as
+ *    being the original software.
+ *
+ * 3. This notice may not be removed or altered from
+ *    any source distribution.
+ */
+
+/*
+ * CRC32 algorithm taken from the zlib source, which is
+ * Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
+ */
+
+#include "tinf.h"
+
+static const unsigned int tinf_crc32tab[16] = {
+   0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190,
+   0x6b6b51f4, 0x4db26158, 0x5005713c, 0xedb88320, 0xf00f9344,
+   0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278,
+   0xbdbdf21c
+};
+
+/* crc is previous value for incremental computation, 0xffffffff initially */
+unsigned int uzlib_crc32(const void *data, unsigned int length, unsigned int crc)
+{
+   const unsigned char *buf = (const unsigned char *)data;
+   unsigned int i;
+
+   for (i = 0; i < length; ++i)
+   {
+      crc ^= buf[i];
+      crc = tinf_crc32tab[crc & 0x0f] ^ (crc >> 4);
+      crc = tinf_crc32tab[crc & 0x0f] ^ (crc >> 4);
+   }
+
+   // return value suitable for passing in next time, for final value invert it
+   return crc/* ^ 0xffffffff*/;
+}
diff --git a/extmod/uzlib/tinf.h b/extmod/uzlib/tinf.h
index e9401f2de5..3545bbd883 100644
--- a/extmod/uzlib/tinf.h
+++ b/extmod/uzlib/tinf.h
@@ -5,7 +5,7 @@
  * All Rights Reserved
  * http://www.ibsensoftware.com/
  *
- * Copyright (c) 2014 by Paul Sokolovsky
+ * Copyright (c) 2014-2016 by Paul Sokolovsky
  */
 
 #ifndef TINF_H_INCLUDED
@@ -26,9 +26,17 @@
 extern "C" {
 #endif
 
+/* ok status, more data produced */
 #define TINF_OK             0
+/* end of compressed stream reached */
+#define TINF_DONE           1
 #define TINF_DATA_ERROR    (-3)
-#define TINF_DEST_OVERFLOW (-4)
+#define TINF_CHKSUM_ERROR  (-4)
+
+/* checksum types */
+#define TINF_CHKSUM_NONE  0
+#define TINF_CHKSUM_ADLER 1
+#define TINF_CHKSUM_CRC   2
 
 /* data structures */
 
@@ -40,6 +48,10 @@ typedef struct {
 struct TINF_DATA;
 typedef struct TINF_DATA {
    const unsigned char *source;
+   /* If source above is NULL, this function will be used to read
+      next byte from source stream */
+   unsigned char (*readSource)(struct TINF_DATA *data);
+
    unsigned int tag;
    unsigned int bitcount;
 
@@ -51,49 +63,51 @@ typedef struct TINF_DATA {
     unsigned char *dest;
     /* Remaining bytes in buffer */
     unsigned int destRemaining;
-    /* Argument is the allocation size which didn't fit into buffer. Note that
-       exact mimumum size to grow buffer by is lastAlloc - destRemaining. But
-       growing by this exact size is ineficient, as the next allocation will
-       fail again. */
-    int (*destGrow)(struct TINF_DATA *data, unsigned int lastAlloc);
+
+    /* Accumulating checksum */
+    unsigned int checksum;
+    char checksum_type;
+
+    int btype;
+    int bfinal;
+    unsigned int curlen;
+    int lzOff;
+    unsigned char *dict_ring;
+    unsigned int dict_size;
+    unsigned int dict_idx;
 
    TINF_TREE ltree; /* dynamic length/symbol tree */
    TINF_TREE dtree; /* dynamic distance tree */
 } TINF_DATA;
 
+#define TINF_PUT(d, c) \
+    { \
+        *d->dest++ = c; \
+        if (d->dict_ring) { d->dict_ring[d->dict_idx++] = c; if (d->dict_idx == d->dict_size) d->dict_idx = 0; } \
+    }
 
-/* low-level API */
+unsigned char TINFCC uzlib_get_byte(TINF_DATA *d);
 
-/* Step 1: Allocate TINF_DATA structure */
-/* Step 2: Set destStart, destSize, and destGrow fields */
-/* Step 3: Set source field */
-/* Step 4: Call tinf_uncompress_dyn() */
-/* Step 5: In response to destGrow callback, update destStart and destSize fields */
-/* Step 6: When tinf_uncompress_dyn() returns, buf.dest points to a byte past last uncompressed byte */
+/* Decompression API */
 
-int TINFCC tinf_uncompress_dyn(TINF_DATA *d);
-int TINFCC tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen);
+void TINFCC uzlib_init(void);
+void TINFCC uzlib_uncompress_init(TINF_DATA *d, void *dict, unsigned int dictLen);
+int  TINFCC uzlib_uncompress(TINF_DATA *d);
+int  TINFCC uzlib_uncompress_chksum(TINF_DATA *d);
 
-/* high-level API */
+int TINFCC uzlib_zlib_parse_header(TINF_DATA *d);
+int TINFCC uzlib_gzip_parse_header(TINF_DATA *d);
 
-void TINFCC tinf_init(void);
+/* Compression API */
 
-int TINFCC tinf_uncompress(void *dest, unsigned int *destLen,
-                           const void *source, unsigned int sourceLen);
+void TINFCC uzlib_compress(void *data, const uint8_t *src, unsigned slen);
 
-int TINFCC tinf_gzip_uncompress(void *dest, unsigned int *destLen,
-                                const void *source, unsigned int sourceLen);
+/* Checksum API */
 
-int TINFCC tinf_zlib_uncompress(void *dest, unsigned int *destLen,
-                                const void *source, unsigned int sourceLen);
-
-unsigned int TINFCC tinf_adler32(const void *data, unsigned int length);
-
-unsigned int TINFCC tinf_crc32(const void *data, unsigned int length);
-
-/* compression API */
-
-void TINFCC tinf_compress(void *data, const uint8_t *src, unsigned slen);
+/* prev_sum is previous value for incremental computation, 1 initially */
+uint32_t TINFCC uzlib_adler32(const void *data, unsigned int length, uint32_t prev_sum);
+/* crc is previous value for incremental computation, 0xffffffff initially */
+uint32_t TINFCC uzlib_crc32(const void *data, unsigned int length, uint32_t crc);
 
 #ifdef __cplusplus
 } /* extern "C" */
diff --git a/extmod/uzlib/tinflate.c b/extmod/uzlib/tinflate.c
index faf27e5739..47644bfcb8 100644
--- a/extmod/uzlib/tinflate.c
+++ b/extmod/uzlib/tinflate.c
@@ -5,7 +5,7 @@
  * All Rights Reserved
  * http://www.ibsensoftware.com/
  *
- * Copyright (c) 2014 by Paul Sokolovsky
+ * Copyright (c) 2014-2016 by Paul Sokolovsky
  *
  * This software is provided 'as-is', without any express
  * or implied warranty.  In no event will the authors be
@@ -32,6 +32,7 @@
  *    any source distribution.
  */
 
+#include <assert.h>
 #include "tinf.h"
 
 /* --------------------------------------------------- *
@@ -89,21 +90,6 @@ const unsigned char clcidx[] = {
  * -- utility functions -- *
  * ----------------------- */
 
-/* Execute callback to grow destination buffer */
-static int tinf_grow_dest_buf(TINF_DATA *d, unsigned int lastAlloc)
-{
-   unsigned int oldsize = d->dest - d->destStart;
-   /* This will update only destStart and destSize */
-   if (!d->destGrow)
-   {
-      return TINF_DEST_OVERFLOW;
-   }
-   d->destGrow(d, lastAlloc);
-   d->dest = d->destStart + oldsize;
-   d->destRemaining = d->destSize - oldsize;
-   return 0;
-}
-
 #ifdef RUNTIME_BITS_TABLES
 /* build extra bits and base tables */
 static void tinf_build_bits_base(unsigned char *bits, unsigned short *base, int delta, int first)
@@ -180,6 +166,34 @@ static void tinf_build_tree(TINF_TREE *t, const unsigned char *lengths, unsigned
  * -- decode functions -- *
  * ---------------------- */
 
+unsigned char uzlib_get_byte(TINF_DATA *d)
+{
+    if (d->source) {
+        return *d->source++;
+    }
+    return d->readSource(d);
+}
+
+uint32_t tinf_get_le_uint32(TINF_DATA *d)
+{
+    uint32_t val = 0;
+    int i;
+    for (i = 4; i--;) {
+        val = val >> 8 | uzlib_get_byte(d) << 24;
+    }
+    return val;
+}
+
+uint32_t tinf_get_be_uint32(TINF_DATA *d)
+{
+    uint32_t val = 0;
+    int i;
+    for (i = 4; i--;) {
+        val = val << 8 | uzlib_get_byte(d);
+    }
+    return val;
+}
+
 /* get one bit from source stream */
 static int tinf_getbit(TINF_DATA *d)
 {
@@ -189,7 +203,7 @@ static int tinf_getbit(TINF_DATA *d)
    if (!d->bitcount--)
    {
       /* load next tag */
-      d->tag = *d->source++;
+      d->tag = uzlib_get_byte(d);
       d->bitcount = 7;
    }
 
@@ -318,113 +332,83 @@ static void tinf_decode_trees(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
 /* given a stream and two trees, inflate a block of data */
 static int tinf_inflate_block_data(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
 {
-   while (1)
-   {
-      int sym = tinf_decode_symbol(d, lt);
+    if (d->curlen == 0) {
+        unsigned int offs;
+        int dist;
+        int sym = tinf_decode_symbol(d, lt);
+        //printf("huff sym: %02x\n", sym);
 
-      /* check for end of block */
-      if (sym == 256)
-      {
-         return TINF_OK;
-      }
+        /* literal byte */
+        if (sym < 256) {
+            TINF_PUT(d, sym);
+            return TINF_OK;
+        }
 
-      if (sym < 256)
-      {
-         if (d->destRemaining == 0)
-         {
-            int res = tinf_grow_dest_buf(d, 1);
-            if (res) return res;
-         }
+        /* end of block */
+        if (sym == 256) {
+            return TINF_DONE;
+        }
 
-         *d->dest++ = sym;
-         d->destRemaining--;
+        /* substring from sliding dictionary */
+        sym -= 257;
+        /* possibly get more bits from length code */
+        d->curlen = tinf_read_bits(d, length_bits[sym], length_base[sym]);
 
-      } else {
+        dist = tinf_decode_symbol(d, dt);
+        /* possibly get more bits from distance code */
+        offs = tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
+        if (d->dict_ring) {
+            d->lzOff = d->dict_idx - offs;
+            if (d->lzOff < 0) {
+                d->lzOff += d->dict_size;
+            }
+        } else {
+            d->lzOff = -offs;
+        }
+    }
 
-         unsigned int length, offs, i;
-         int dist;
-
-         sym -= 257;
-
-         /* possibly get more bits from length code */
-         length = tinf_read_bits(d, length_bits[sym], length_base[sym]);
-
-         dist = tinf_decode_symbol(d, dt);
-
-         /* possibly get more bits from distance code */
-         offs = tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
-
-         if (d->destRemaining < length)
-         {
-            int res = tinf_grow_dest_buf(d, length);
-            if (res) return res;
-         }
-
-         /* copy match */
-         for (i = 0; i < length; ++i)
-         {
-            d->dest[i] = d->dest[(int)(i - offs)];
-         }
-
-         d->dest += length;
-         d->destRemaining -= length;
-      }
-   }
+    /* copy next byte from dict substring */
+    if (d->dict_ring) {
+        TINF_PUT(d, d->dict_ring[d->lzOff]);
+        if (++d->lzOff == d->dict_size) {
+            d->lzOff = 0;
+        }
+    } else {
+        d->dest[0] = d->dest[d->lzOff];
+        d->dest++;
+    }
+    d->curlen--;
+    return TINF_OK;
 }
 
 /* inflate an uncompressed block of data */
 static int tinf_inflate_uncompressed_block(TINF_DATA *d)
 {
-   unsigned int length, invlength;
-   unsigned int i;
+    if (d->curlen == 0) {
+        unsigned int length, invlength;
 
-   /* get length */
-   length = d->source[1];
-   length = 256*length + d->source[0];
+        /* get length */
+        length = uzlib_get_byte(d) + 256 * uzlib_get_byte(d);
+        /* get one's complement of length */
+        invlength = uzlib_get_byte(d) + 256 * uzlib_get_byte(d);
+        /* check length */
+        if (length != (~invlength & 0x0000ffff)) return TINF_DATA_ERROR;
 
-   /* get one's complement of length */
-   invlength = d->source[3];
-   invlength = 256*invlength + d->source[2];
+        /* increment length to properly return TINF_DONE below, without
+           producing data at the same time */
+        d->curlen = length + 1;
 
-   /* check length */
-   if (length != (~invlength & 0x0000ffff)) return TINF_DATA_ERROR;
+        /* make sure we start next block on a byte boundary */
+        d->bitcount = 0;
+    }
 
-   if (d->destRemaining < length)
-   {
-      int res = tinf_grow_dest_buf(d, length);
-      if (res) return res;
-   }
+    if (--d->curlen == 0) {
+        return TINF_DONE;
+    }
 
-   d->source += 4;
-
-   /* copy block */
-   for (i = length; i; --i) *d->dest++ = *d->source++;
-   d->destRemaining -= length;
-
-   /* make sure we start next block on a byte boundary */
-   d->bitcount = 0;
-
-   return TINF_OK;
-}
-
-/* inflate a block of data compressed with fixed huffman trees */
-static int tinf_inflate_fixed_block(TINF_DATA *d)
-{
-   /* build fixed huffman trees */
-   tinf_build_fixed_trees(&d->ltree, &d->dtree);
-
-   /* decode block using fixed trees */
-   return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
-}
-
-/* inflate a block of data compressed with dynamic huffman trees */
-static int tinf_inflate_dynamic_block(TINF_DATA *d)
-{
-   /* decode trees from stream */
-   tinf_decode_trees(d, &d->ltree, &d->dtree);
-
-   /* decode block using decoded trees */
-   return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
+    unsigned char c = uzlib_get_byte(d);
+    TINF_PUT(d, c);
+    return TINF_OK;
 }
 
 /* ---------------------- *
@@ -432,7 +416,7 @@ static int tinf_inflate_dynamic_block(TINF_DATA *d)
  * ---------------------- */
 
 /* initialize global (static) data */
-void tinf_init(void)
+void uzlib_init(void)
 {
 #ifdef RUNTIME_BITS_TABLES
    /* build extra bits and base tables */
@@ -445,72 +429,117 @@ void tinf_init(void)
 #endif
 }
 
-/* inflate stream from source to dest */
-int tinf_uncompress(void *dest, unsigned int *destLen,
-                    const void *source, unsigned int sourceLen)
+/* initialize decompression structure */
+void uzlib_uncompress_init(TINF_DATA *d, void *dict, unsigned int dictLen)
 {
-   (void)sourceLen;
-   TINF_DATA d;
-   int res;
-
-   /* initialise data */
-   d.source = (const unsigned char *)source;
-
-   d.destStart = (unsigned char *)dest;
-   d.destRemaining = *destLen;
-   d.destSize = *destLen;
-
-   res = tinf_uncompress_dyn(&d);
-
-   *destLen = d.dest - d.destStart;
-
-   return res;
-}
-
-/* inflate stream from source to dest */
-int tinf_uncompress_dyn(TINF_DATA *d)
-{
-   int bfinal;
-
-   /* initialise data */
    d->bitcount = 0;
-
-   d->dest = d->destStart;
-   d->destRemaining = d->destSize;
-
-   do {
-
-      unsigned int btype;
-      int res;
-
-      /* read final block flag */
-      bfinal = tinf_getbit(d);
-
-      /* read block type (2 bits) */
-      btype = tinf_read_bits(d, 2, 0);
-
-      /* decompress block */
-      switch (btype)
-      {
-      case 0:
-         /* decompress uncompressed block */
-         res = tinf_inflate_uncompressed_block(d);
-         break;
-      case 1:
-         /* decompress block with fixed huffman trees */
-         res = tinf_inflate_fixed_block(d);
-         break;
-      case 2:
-         /* decompress block with dynamic huffman trees */
-         res = tinf_inflate_dynamic_block(d);
-         break;
-      default:
-         return TINF_DATA_ERROR;
-      }
-
-      if (res != TINF_OK) return TINF_DATA_ERROR;
-
-   } while (!bfinal);
-
-   return TINF_OK;
+   d->bfinal = 0;
+   d->btype = -1;
+   d->dict_size = dictLen;
+   d->dict_ring = dict;
+   d->dict_idx = 0;
+   d->curlen = 0;
+}
+
+/* inflate next byte of compressed stream */
+int uzlib_uncompress(TINF_DATA *d)
+{
+    do {
+        int res;
+
+        /* start a new block */
+        if (d->btype == -1) {
+next_blk:
+            /* read final block flag */
+            d->bfinal = tinf_getbit(d);
+            /* read block type (2 bits) */
+            d->btype = tinf_read_bits(d, 2, 0);
+
+            //printf("Started new block: type=%d final=%d\n", d->btype, d->bfinal);
+
+            if (d->btype == 1) {
+                /* build fixed huffman trees */
+                tinf_build_fixed_trees(&d->ltree, &d->dtree);
+            } else if (d->btype == 2) {
+                /* decode trees from stream */
+                tinf_decode_trees(d, &d->ltree, &d->dtree);
+            }
+        }
+
+        /* process current block */
+        switch (d->btype)
+        {
+        case 0:
+            /* decompress uncompressed block */
+            res = tinf_inflate_uncompressed_block(d);
+            break;
+        case 1:
+        case 2:
+            /* decompress block with fixed/dyanamic huffman trees */
+            /* trees were decoded previously, so it's the same routine for both */
+            res = tinf_inflate_block_data(d, &d->ltree, &d->dtree);
+            break;
+        default:
+            return TINF_DATA_ERROR;
+        }
+
+        if (res == TINF_DONE && !d->bfinal) {
+            /* the block has ended (without producing more data), but we
+               can't return without data, so start procesing next block */
+            goto next_blk;
+        }
+
+        if (res != TINF_OK) {
+            return res;
+        }
+
+    } while (--d->destSize);
+
+    return TINF_OK;
+}
+
+int uzlib_uncompress_chksum(TINF_DATA *d)
+{
+    int res;
+    unsigned char *data = d->dest;
+
+    res = uzlib_uncompress(d);
+
+    if (res < 0) return res;
+
+    switch (d->checksum_type) {
+
+    case TINF_CHKSUM_ADLER:
+        d->checksum = uzlib_adler32(data, d->dest - data, d->checksum);
+        break;
+
+    case TINF_CHKSUM_CRC:
+        d->checksum = uzlib_crc32(data, d->dest - data, d->checksum);
+        break;
+    }
+
+    if (res == TINF_DONE) {
+        unsigned int val;
+
+        switch (d->checksum_type) {
+
+        case TINF_CHKSUM_ADLER:
+            val = tinf_get_be_uint32(d);
+            if (d->checksum != val) {
+                return TINF_CHKSUM_ERROR;
+            }
+            break;
+
+        case TINF_CHKSUM_CRC:
+            val = tinf_get_le_uint32(d);
+            if (~d->checksum != val) {
+                return TINF_CHKSUM_ERROR;
+            }
+            // Uncompressed size. TODO: Check
+            val = tinf_get_le_uint32(d);
+            break;
+        }
+    }
+
+    return res;
 }
diff --git a/extmod/uzlib/tinfzlib.c b/extmod/uzlib/tinfzlib.c
index dbacc1d9db..74fade3b9d 100644
--- a/extmod/uzlib/tinfzlib.c
+++ b/extmod/uzlib/tinfzlib.c
@@ -6,6 +6,8 @@
  *
  * http://www.ibsensoftware.com/
  *
+ * Copyright (c) 2014-2016 by Paul Sokolovsky
+ *
  * This software is provided 'as-is', without any express
  * or implied warranty.  In no event will the authors be
  * held liable for any damages arising from the use of
@@ -33,35 +35,14 @@
 
 #include "tinf.h"
 
-int tinf_zlib_uncompress(void *dest, unsigned int *destLen,
-                         const void *source, unsigned int sourceLen)
+int uzlib_zlib_parse_header(TINF_DATA *d)
 {
-   TINF_DATA d;
-   int res;
-
-   /* initialise data */
-   d.source = (const unsigned char *)source;
-
-   d.destStart = (unsigned char *)dest;
-   d.destRemaining = *destLen;
-
-   res = tinf_zlib_uncompress_dyn(&d, sourceLen);
-
-   *destLen = d.dest - d.destStart;
-
-   return res;
-}
-
-int tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen)
-{
-   unsigned int a32;
-   int res;
    unsigned char cmf, flg;
 
    /* -- get header bytes -- */
 
-   cmf = d->source[0];
-   flg = d->source[1];
+   cmf = uzlib_get_byte(d);
+   flg = uzlib_get_byte(d);
 
    /* -- check format -- */
 
@@ -77,25 +58,9 @@ int tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen)
    /* check there is no preset dictionary */
    if (flg & 0x20) return TINF_DATA_ERROR;
 
-   /* -- get adler32 checksum -- */
+   /* initialize for adler32 checksum */
+   d->checksum_type = TINF_CHKSUM_ADLER;
+   d->checksum = 1;
 
-   a32 =           d->source[sourceLen - 4];
-   a32 = 256*a32 + d->source[sourceLen - 3];
-   a32 = 256*a32 + d->source[sourceLen - 2];
-   a32 = 256*a32 + d->source[sourceLen - 1];
-
-   d->source += 2;
-
-   /* -- inflate -- */
-
-   res = tinf_uncompress_dyn(d);
-
-   if (res != TINF_OK) return res;
-
-   /* -- check adler32 checksum -- */
-
-   if (a32 != tinf_adler32(d->destStart, d->dest - d->destStart)) return TINF_DATA_ERROR;
-
-   return TINF_OK;
+   return cmf >> 4;
 }
-