diff --git a/scripts/mbedtls_dev/ecp.py b/scripts/mbedtls_dev/ecp.py
index 6d3bb05..10fcc5e 100644
--- a/scripts/mbedtls_dev/ecp.py
+++ b/scripts/mbedtls_dev/ecp.py
@@ -144,12 +144,13 @@
     def is_valid(self) -> bool:
         return True
 
-class EcpPp384R1Raw(bignum_common.ModOperationCommon,
-                    EcpTarget):
+
+class EcpP384R1Raw(bignum_common.ModOperationCommon,
+                   EcpTarget):
     """Test cases for ecp quasi_reduction modulo p384."""
     test_function = "ecp_mod_p384_raw"
     test_name = "ecp_mod_p384_raw"
-    input_style = "arch_split"
+    input_style = "fixed"
     arity = 1
 
     moduli = [("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
@@ -164,7 +165,7 @@
          "fffffff0000000000000000fffffffe"),
 
         # Maximum canonical P384 multiplication result
-        ("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
+        ("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
          "fdfffffffe0000000000000001fffffffc0000000000000000000000000000000"
          "10000000200000000fffffffe000000020000000400000000fffffffc00000004"),
 
@@ -178,6 +179,16 @@
          "b68abef41dbd35183a0614fb7222606ffffffff84396eee542f18a9189d94396c"
          "784059c17a9f18f807214ef32f2f10ffffffff8a77fac20000000000000000"),
 
+        # Testing with overflow in A(23) + A(20) + A(19) - A(22);
+        ("783753f8a5afba6c1862eead1deb2fcdd907272be3ffd18542b24a71ee8b26ca"
+         "b0aa33513610ff973042bbe1637cc9fc99ad36c7f703514572cf4f5c3044469a"
+         "8f5be6312c19e5d3f8fc1ac6ffffffffffffffff8c86252400000000ffffffff"),
+
+        # Testing with underflow in A(23) + A(20) + A(19) - A(22);
+        ("65e1d2362fce922663b7fd517586e88842a9b4bd092e93e6251c9c69f278cbf8"
+         "285d99ae3b53da5ba36e56701e2b17c225f1239556c5f00117fa140218b46ebd8"
+         "e34f50d0018701fa8a0a5cc00000000000000004410bcb4ffffffff00000000"),
+
         # First 8 number generated by random.getrandbits(768) - seed(2,2)
         ("ffed9235288bc781ae66267594c9c9500925e4749b575bd13653f8dd9b1f282e"
          "4067c3584ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5e34124"
@@ -213,9 +224,7 @@
 
     @property
     def arg_a(self) -> str:
-        hex_digits = bignum_common.hex_digits_for_limb((766 // self.bits_in_limb) + 1,
-                                                       self.bits_in_limb)
-        return super().format_arg('{:x}'.format(self.int_a)).zfill(hex_digits)
+        return super().format_arg('{:x}'.format(self.int_a)).zfill(2 * self.hex_digits)
 
     def result(self) -> List[str]:
         result = self.int_a % self.int_n