diff --git a/src/krux/bip39.py b/src/krux/bip39.py
index 0fe2e9ea..c52a21b1 100644
--- a/src/krux/bip39.py
+++ b/src/krux/bip39.py
@@ -1,5 +1,5 @@
 # Mnemonic convertion to seed and to/from bytes
-#pylint: disable=W0102
+# pylint: disable=W0102
 
 import hashlib
 from embit.wordlists.bip39 import WORDLIST
@@ -7,9 +7,7 @@
 WORDINDEX = {word: i for i, word in enumerate(WORDLIST)}
 
 
-def mnemonic_to_bytes(
-    mnemonic: str, ignore_checksum: bool = False, wordlist=WORDLIST
-):
+def mnemonic_to_bytes(mnemonic: str, ignore_checksum: bool = False, wordlist=WORDLIST):
     """Verifies the mnemonic checksum and returns it in bytes"""
     words = mnemonic.strip().split()
     if len(words) % 3 != 0 or len(words) < 12:
diff --git a/src/krux/wallet.py b/src/krux/wallet.py
index 8ee075f6..92ebc609 100644
--- a/src/krux/wallet.py
+++ b/src/krux/wallet.py
@@ -462,7 +462,6 @@ def is_double_mnemonic(mnemonic: str):
 
     words = mnemonic.split(" ")
     if len(words) > 12:
-        from embit import bip39
         from krux import bip39 as kruxbip39
 
         # use an optimized version of mnemonic_to_bytes() via kruxbip39
@@ -471,12 +470,6 @@ def is_double_mnemonic(mnemonic: str):
             and kruxbip39.mnemonic_is_valid(" ".join(words[12:]))
             and kruxbip39.mnemonic_is_valid(mnemonic)
         ):
-            # verify the well-known/well-tested version from embit.bip39
-            if (
-                bip39.mnemonic_is_valid(" ".join(words[:12]))
-                and bip39.mnemonic_is_valid(" ".join(words[12:]))
-                and bip39.mnemonic_is_valid(mnemonic)
-            ):
-                return True
+            return True
 
     return False
diff --git a/tests/test_bip39.py b/tests/test_bip39.py
new file mode 100644
index 00000000..527c58e0
--- /dev/null
+++ b/tests/test_bip39.py
@@ -0,0 +1,56 @@
+from krux import bip39 as kruxbip39
+from embit import bip39
+from embit.wordlists.bip39 import WORDLIST
+import secrets
+
+
+def test_one_word_mnemonics():
+    for word in WORDLIST:
+        mnemonic = (word + " ") * 12
+        assert kruxbip39.mnemonic_is_valid(mnemonic) == bip39.mnemonic_is_valid(
+            mnemonic
+        )
+
+    for word in WORDLIST:
+        mnemonic = (word + " ") * 24
+        assert kruxbip39.mnemonic_is_valid(mnemonic) == bip39.mnemonic_is_valid(
+            mnemonic
+        )
+
+
+def test_edge_cases():
+    cases = [8, 16]  # 12w and 24w
+    for case in cases:
+        ALL_ZERO_BYTES = int(0).to_bytes(16, "big")
+        ALL_ONE_BYTES = int.from_bytes(bytearray([255] * case)).to_bytes(16, "big")
+
+        assert (
+            kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(ALL_ZERO_BYTES))
+            == ALL_ZERO_BYTES
+        )
+        assert (
+            kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(ALL_ONE_BYTES))
+            == ALL_ONE_BYTES
+        )
+
+        int_val = max_val = int.from_bytes(ALL_ONE_BYTES)
+        while int_val > 0:
+            int_val = int_val // 2
+            b = int_val.to_bytes(16, "big")
+            assert kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(b)) == b
+
+            b = (max_val - int_val).to_bytes(16, "big")
+            assert kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(b)) == b
+
+
+def test_random_cases():
+    for _ in range(20000):
+        token12w = secrets.token_bytes(16)
+        token24w = secrets.token_bytes(32)
+
+        assert (
+            kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(token12w)) == token12w
+        )
+        assert (
+            kruxbip39.mnemonic_to_bytes(bip39.mnemonic_from_bytes(token24w)) == token24w
+        )