diff --git a/py/makeqstrdata.py b/py/makeqstrdata.py
index e332ab94e..78e829e3e 100644
--- a/py/makeqstrdata.py
+++ b/py/makeqstrdata.py
@@ -347,12 +347,21 @@ def print_qstr_data(qcfgs, qstrs):
     print("")
 
     # add NULL qstr with no hash or data
-    print('QDEF(MP_QSTRnull, 0, 0, "")')
+    print('QDEF0(MP_QSTRnull, 0, 0, "")')
 
-    # go through each qstr and print it out
-    for order, ident, qstr in sorted(qstrs.values(), key=lambda x: x[0]):
+    # split qstr values into two pools. static consts first.
+    q0_values = [q for q in qstrs.values() if q[0] < 0]
+    q1_values = [q for q in qstrs.values() if q[0] >= 0]
+
+    # go through each qstr in pool 0 and print it out. pool0 has special sort.
+    for order, ident, qstr in sorted(q0_values, key=lambda x: x[0]):
         qbytes = make_bytes(cfg_bytes_len, cfg_bytes_hash, qstr)
-        print("QDEF(MP_QSTR_%s, %s)" % (ident, qbytes))
+        print("QDEF0(MP_QSTR_%s, %s)" % (ident, qbytes))
+
+    # go through each qstr in pool 1 and print it out. pool1 is regularly sorted.
+    for order, ident, qstr in sorted(q1_values, key=lambda x: x[2]):
+        qbytes = make_bytes(cfg_bytes_len, cfg_bytes_hash, qstr)
+        print("QDEF1(MP_QSTR_%s, %s)" % (ident, qbytes))
 
 
 def do_work(infiles):
diff --git a/py/qstr.c b/py/qstr.c
index f9ca10683..7a06d956d 100644
--- a/py/qstr.c
+++ b/py/qstr.c
@@ -74,34 +74,82 @@ mp_uint_t qstr_compute_hash(const byte *data, size_t len) {
     return hash;
 }
 
-const qstr_hash_t mp_qstr_const_hashes[] = {
+const qstr_hash_t mp_qstr_const_hashes0[] = {
     #ifndef NO_QSTR
-#define QDEF(id, hash, len, str) hash,
+#define QDEF0(id, hash, len, str) hash,
+#define QDEF1(id, hash, len, str)
     #include "genhdr/qstrdefs.generated.h"
-#undef QDEF
+#undef QDEF0
+#undef QDEF1
     #endif
 };
 
-const qstr_len_t mp_qstr_const_lengths[] = {
+const qstr_hash_t mp_qstr_const_hashes1[] = {
     #ifndef NO_QSTR
-#define QDEF(id, hash, len, str) len,
+#define QDEF0(id, hash, len, str)
+#define QDEF1(id, hash, len, str) hash,
     #include "genhdr/qstrdefs.generated.h"
-#undef QDEF
+#undef QDEF0
+#undef QDEF1
     #endif
 };
 
+const qstr_len_t mp_qstr_const_lengths0[] = {
+    #ifndef NO_QSTR
+#define QDEF0(id, hash, len, str) len,
+#define QDEF1(id, hash, len, str)
+    #include "genhdr/qstrdefs.generated.h"
+#undef QDEF0
+#undef QDEF1
+    #endif
+};
+
+const qstr_len_t mp_qstr_const_lengths1[] = {
+    #ifndef NO_QSTR
+#define QDEF0(id, hash, len, str)
+#define QDEF1(id, hash, len, str) len,
+    #include "genhdr/qstrdefs.generated.h"
+#undef QDEF0
+#undef QDEF1
+    #endif
+};
+
+const qstr_pool_t mp_qstr_special_const_pool = {
+    NULL,                        // no previous pool
+    0,                           // no previous pool
+    MICROPY_ALLOC_QSTR_ENTRIES_INIT,
+    MP_QSTRspecial_const_number_of + 1, // corresponds to number of strings in array just below
+    (qstr_hash_t *)mp_qstr_const_hashes0,
+    (qstr_len_t *)mp_qstr_const_lengths0,
+    false,                       // special constant qstrs are not sorted
+    {
+        #ifndef NO_QSTR
+#define QDEF0(id, hash, len, str) str,
+#define QDEF1(id, hash, len, str)
+        #include "genhdr/qstrdefs.generated.h"
+#undef QDEF0
+#undef QDEF1
+        #endif
+        (const char *)"",       // spacer for MP_QSTRspecial_const_number_of
+    },
+};
+
 const qstr_pool_t mp_qstr_const_pool = {
-    NULL,               // no previous pool
-    0,                  // no previous pool
+    (qstr_pool_t *)&mp_qstr_special_const_pool,
+    MP_QSTRspecial_const_number_of + 1,
     MICROPY_ALLOC_QSTR_ENTRIES_INIT,
-    MP_QSTRnumber_of,   // corresponds to number of strings in array just below
-    (qstr_hash_t *)mp_qstr_const_hashes,
-    (qstr_len_t *)mp_qstr_const_lengths,
+    MP_QSTRnumber_of -
+    (MP_QSTRspecial_const_number_of + 1),      // corresponds to number of strings in array just below
+    (qstr_hash_t *)mp_qstr_const_hashes1,
+    (qstr_len_t *)mp_qstr_const_lengths1,
+    true,                               // constant qstrs are sorted
     {
         #ifndef NO_QSTR
-#define QDEF(id, hash, len, str) str,
+#define QDEF0(id, hash, len, str)
+#define QDEF1(id, hash, len, str) str,
         #include "genhdr/qstrdefs.generated.h"
-#undef QDEF
+#undef QDEF0
+#undef QDEF1
         #endif
     },
 };
@@ -164,6 +212,7 @@ STATIC qstr qstr_add(mp_uint_t hash, mp_uint_t len, const char *q_ptr) {
         pool->total_prev_len = MP_STATE_VM(last_pool)->total_prev_len + MP_STATE_VM(last_pool)->len;
         pool->alloc = new_alloc;
         pool->len = 0;
+        pool->sorted = false;
         MP_STATE_VM(last_pool) = pool;
         DEBUG_printf("QSTR: allocate new pool of size %d\n", MP_STATE_VM(last_pool)->alloc);
     }
@@ -179,13 +228,43 @@ STATIC qstr qstr_add(mp_uint_t hash, mp_uint_t len, const char *q_ptr) {
     return MP_STATE_VM(last_pool)->total_prev_len + at;
 }
 
+#define MP_QSTR_SEARCH_THRESHOLD 10
+
 qstr qstr_find_strn(const char *str, size_t str_len) {
-    // work out hash of str
     mp_uint_t str_hash = qstr_compute_hash((const byte *)str, str_len);
 
     // search pools for the data
     for (const qstr_pool_t *pool = MP_STATE_VM(last_pool); pool != NULL; pool = pool->prev) {
-        for (mp_uint_t at = 0, top = pool->len; at < top; at++) {
+        size_t low = 0;
+        size_t high = pool->len - 1;
+
+        // binary search inside the pool
+        if (pool->sorted) {
+            while (high - low > MP_QSTR_SEARCH_THRESHOLD) {
+                size_t mid = (low + high + 1) / 2;
+                size_t len = pool->lengths[mid];
+                if (len > str_len) {
+                    len = str_len;
+                }
+                int cmp = memcmp(pool->qstrs[mid], str, str_len);
+                if (cmp < 0) {
+                    low = mid;
+                } else if (cmp > 0) {
+                    high = mid;
+                } else {
+                    if (pool->lengths[mid] < str_len) {
+                        low = mid;
+                    } else if (pool->lengths[mid] > str_len) {
+                        high = mid;
+                    } else {
+                        return pool->total_prev_len + mid;
+                    }
+                }
+            }
+        }
+
+        // sequential search for the remaining strings
+        for (mp_uint_t at = low; at < high + 1; at++) {
             if (pool->hashes[at] == str_hash && pool->lengths[at] == str_len
                 && memcmp(pool->qstrs[at], str, str_len) == 0) {
                 return pool->total_prev_len + at;
diff --git a/py/qstr.h b/py/qstr.h
index fa634f90b..6a2098217 100644
--- a/py/qstr.h
+++ b/py/qstr.h
@@ -38,9 +38,21 @@
 // first entry in enum will be MP_QSTRnull=0, which indicates invalid/no qstr
 enum {
     #ifndef NO_QSTR
-#define QDEF(id, hash, len, str) id,
+
+#define QDEF0(id, hash, len, str) id,
+#define QDEF1(id, hash, len, str)
     #include "genhdr/qstrdefs.generated.h"
-#undef QDEF
+#undef QDEF0
+#undef QDEF1
+
+    MP_QSTRspecial_const_number_of, // no underscore so it can't clash with any of the above
+
+#define QDEF0(id, hash, len, str)
+#define QDEF1(id, hash, len, str) id,
+    #include "genhdr/qstrdefs.generated.h"
+#undef QDEF0
+#undef QDEF1
+
     #endif
     MP_QSTRnumber_of, // no underscore so it can't clash with any of the above
 };
@@ -71,6 +83,7 @@ typedef struct _qstr_pool_t {
     size_t len;
     qstr_hash_t *hashes;
     qstr_len_t *lengths;
+    bool sorted;
     const char *qstrs[];
 } qstr_pool_t;
 
diff --git a/tools/makemanifest.py b/tools/makemanifest.py
index 8cdc3eb77..c3df17755 100644
--- a/tools/makemanifest.py
+++ b/tools/makemanifest.py
@@ -415,7 +415,7 @@ def main():
             b'#include "py/emitglue.h"\n'
             b"extern const qstr_pool_t mp_qstr_const_pool;\n"
             b"const qstr_pool_t mp_qstr_frozen_const_pool = {\n"
-            b"    (qstr_pool_t*)&mp_qstr_const_pool, MP_QSTRnumber_of, 0, 0\n"
+            b"    (qstr_pool_t*)&mp_qstr_const_pool, MP_QSTRnumber_of, 0, false, 0\n"
             b"};\n"
             b'const char mp_frozen_names[] = { MP_FROZEN_STR_NAMES "\\0"};\n'
             b"const mp_raw_code_t *const mp_frozen_mpy_content[] = {NULL};\n"
diff --git a/tools/mpy-tool.py b/tools/mpy-tool.py
index 31212fd5b..8a6baba6c 100755
--- a/tools/mpy-tool.py
+++ b/tools/mpy-tool.py
@@ -1397,7 +1397,7 @@ def freeze_mpy(base_qstrs, compiled_modules):
         if q is None or q.qstr_esc in base_qstrs or q.qstr_esc in new:
             continue
         new[q.qstr_esc] = (len(new), q.qstr_esc, q.str, bytes_cons(q.str, "utf8"))
-    new = sorted(new.values(), key=lambda x: x[0])
+    new = sorted(new.values(), key=lambda x: x[2])
 
     print('#include "py/mpconfig.h"')
     print('#include "py/objint.h"')
@@ -1482,6 +1482,7 @@ def freeze_mpy(base_qstrs, compiled_modules):
     print("    %u, // used entries" % len(new))
     print("    (qstr_hash_t *)mp_qstr_frozen_const_hashes,")
     print("    (qstr_len_t *)mp_qstr_frozen_const_lengths,")
+    print("    true, // entries are sorted")
     print("    {")
     for _, _, qstr, qbytes in new:
         print('        "%s",' % qstrutil.escape_bytes(qstr, qbytes))