diff --git a/src/compress_lzma.cpp b/src/compress_lzma.cpp
index df04244b..bb570900 100644
--- a/src/compress_lzma.cpp
+++ b/src/compress_lzma.cpp
@@ -193,7 +193,7 @@ int upx_lzma_compress      ( const upx_bytep src, unsigned  src_len,
     pr[2].uintVal = 3;              // 0..8
     pr[3].uintVal = 1024 * 1024;
     pr[4].uintVal = 2;
-    pr[5].uintVal = 64;             // 5..
+    pr[5].uintVal = 64;             // 5..273
     pr[6].uintVal = 0;
 #if 0
     // DEBUG - set sizes so that we use a maxmimum amount of stack.
@@ -209,8 +209,11 @@ int upx_lzma_compress      ( const upx_bytep src, unsigned  src_len,
     case 1:
         pr[3].uintVal = 256 * 1024;
         pr[4].uintVal = 0;
+        pr[5].uintVal = 8;
         break;
     case 2:
+        pr[3].uintVal = 256 * 1024;
+        pr[4].uintVal = 0;
         break;
     case 3:
         break;
@@ -243,6 +246,8 @@ int upx_lzma_compress      ( const upx_bytep src, unsigned  src_len,
             pr[1].uintVal = cconf_parm->conf_lzma.lit_pos_bits;
         if (cconf_parm->conf_lzma.lit_context_bits.is_set)
             pr[2].uintVal = cconf_parm->conf_lzma.lit_context_bits;
+        if (cconf_parm->conf_lzma.num_fast_bytes.is_set)
+            pr[5].uintVal = cconf_parm->conf_lzma.num_fast_bytes;
     }
 
     // limit dictionary size
@@ -276,6 +281,9 @@ int upx_lzma_compress      ( const upx_bytep src, unsigned  src_len,
     res->lit_pos_bits = pr[1].uintVal;
     res->lit_context_bits = pr[2].uintVal;
     res->dict_size = pr[3].uintVal;
+    res->fast_mode = pr[4].uintVal;
+    res->num_fast_bytes = pr[5].uintVal;
+    res->match_finder_cycles = pr[6].uintVal;
     //res->num_probs = LzmaGetNumProbs(&s.Properties));
     //res->num_probs = (LZMA_BASE_SIZE + (LZMA_LIT_SIZE << ((Properties)->lc + (Properties)->lp)))
     res->num_probs = 1846 + (768 << (res->lit_context_bits + res->lit_pos_bits));
diff --git a/src/conf.h b/src/conf.h
index bd49e16a..394e0055 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -239,14 +239,16 @@ struct OptVar
 
 struct lzma_compress_config_t
 {
-    typedef OptVar<unsigned, 2u, 0u, 4u> pos_bits_t;            // pb
-    typedef OptVar<unsigned, 0u, 0u, 4u> lit_pos_bits_t;        // lb
-    typedef OptVar<unsigned, 3u, 0u, 8u> lit_context_bits_t;    // lc
+    typedef OptVar<unsigned,  2u, 0u,   4u> pos_bits_t;             // pb
+    typedef OptVar<unsigned,  0u, 0u,   4u> lit_pos_bits_t;         // lb
+    typedef OptVar<unsigned,  3u, 0u,   8u> lit_context_bits_t;     // lc
+    typedef OptVar<unsigned, 64u, 5u, 273u> num_fast_bytes_t;
 
     unsigned            max_num_probs;
     pos_bits_t          pos_bits;           // pb
     lit_pos_bits_t      lit_pos_bits;       // lp
     lit_context_bits_t  lit_context_bits;   // lc
+    num_fast_bytes_t    num_fast_bytes;
 #if 0
     unsigned dict_size;
     unsigned mf_passes;
@@ -254,6 +256,7 @@ struct lzma_compress_config_t
     void reset() {
         memset(this, 0, sizeof(*this));
         pos_bits.reset(); lit_pos_bits.reset(); lit_context_bits.reset();
+        num_fast_bytes.reset();
     }
 };
 
@@ -276,7 +279,10 @@ struct lzma_compress_result_t
     unsigned lit_pos_bits;          // lp
     unsigned lit_context_bits;      // lc
     unsigned dict_size;
-    unsigned num_probs;
+    unsigned fast_mode;
+    unsigned num_fast_bytes;
+    unsigned match_finder_cycles;
+    unsigned num_probs;             // (computed result)
 };
 
 struct ucl_compress_result_t
diff --git a/src/main.cpp b/src/main.cpp
index b0498f49..5b526592 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -651,6 +651,9 @@ static int do_option(int optc, const char *arg)
     case 813:
         getoptvar(&opt->crp.crp_lzma.lit_context_bits, arg);
         break;
+    case 816:
+        getoptvar(&opt->crp.crp_lzma.num_fast_bytes, arg);
+        break;
     // backup
     case 'k':
         opt->backup = 1;
@@ -898,6 +901,7 @@ static const struct mfx_option longopts[] =
     {"crp-lzma-pb",      0x31, 0, 811},
     {"crp-lzma-lp",      0x31, 0, 812},
     {"crp-lzma-lc",      0x31, 0, 813},
+    {"crp-lzma-fb",      0x31, 0, 816},
 
     // atari/tos
     {"split-segments",   0x10, 0, 650},
diff --git a/src/options.h b/src/options.h
index cc24eba3..2f0ffcaf 100644
--- a/src/options.h
+++ b/src/options.h
@@ -89,6 +89,7 @@ struct options_t {
         TT::pos_bits_t          pos_bits;           // pb
         TT::lit_pos_bits_t      lit_pos_bits;       // lp
         TT::lit_context_bits_t  lit_context_bits;   // lc
+        TT::num_fast_bytes_t    num_fast_bytes;
 #if 0
         unsigned dict_size;
         unsigned mf_passes;
@@ -96,6 +97,7 @@ struct options_t {
         void reset() {
             memset(this, 0, sizeof(*this));
             pos_bits.reset(); lit_pos_bits.reset(); lit_context_bits.reset();
+            num_fast_bytes.reset();
         }
     };
     struct crp_ucl_t {
diff --git a/src/packer.cpp b/src/packer.cpp
index 2dd09cf3..90ec358a 100644
--- a/src/packer.cpp
+++ b/src/packer.cpp
@@ -195,6 +195,7 @@ bool Packer::compress(upx_bytep in, upx_bytep out,
         cconf.conf_lzma.pos_bits = opt->crp.crp_lzma.pos_bits;
         cconf.conf_lzma.lit_pos_bits = opt->crp.crp_lzma.lit_pos_bits;
         cconf.conf_lzma.lit_context_bits = opt->crp.crp_lzma.lit_context_bits;
+        cconf.conf_lzma.num_fast_bytes = opt->crp.crp_lzma.num_fast_bytes;
     }
     if (uip->ui_pass >= 0)
         uip->ui_pass++;