diff --git a/scripts/mbedtls_dev/bignum_common.py b/scripts/mbedtls_dev/bignum_common.py
index e03c1c3f8a..67ea78db46 100644
--- a/scripts/mbedtls_dev/bignum_common.py
+++ b/scripts/mbedtls_dev/bignum_common.py
@@ -93,7 +93,7 @@ class OperationCommon(test_data_generation.BaseTest):
     symbol = ""
     input_values = INPUTS_DEFAULT # type: List[str]
     input_cases = [] # type: List[Any]
-    unique_combinations_only = True
+    unique_combinations_only = False
     input_styles = ["variable", "fixed", "arch_split"] # type: List[str]
     input_style = "variable" # type: str
     limb_sizes = [32, 64] # type: List[int]
diff --git a/scripts/mbedtls_dev/bignum_core.py b/scripts/mbedtls_dev/bignum_core.py
index 806e131935..4910daea87 100644
--- a/scripts/mbedtls_dev/bignum_core.py
+++ b/scripts/mbedtls_dev/bignum_core.py
@@ -114,6 +114,7 @@ class BignumCoreAddAndAddIf(BignumCoreTarget, bignum_common.OperationCommon):
     test_function = "mpi_core_add_and_add_if"
     test_name = "mpi_core_add_and_add_if"
     input_style = "arch_split"
+    unique_combinations_only = True
 
     def result(self) -> List[str]:
         result = self.int_a + self.int_b
@@ -132,7 +133,6 @@ class BignumCoreSub(BignumCoreTarget, bignum_common.OperationCommon):
     symbol = "-"
     test_function = "mpi_core_sub"
     test_name = "mbedtls_mpi_core_sub"
-    unique_combinations_only = False
 
     def result(self) -> List[str]:
         if self.int_a >= self.int_b:
@@ -157,7 +157,6 @@ class BignumCoreMLA(BignumCoreTarget, bignum_common.OperationCommon):
     count = 0
     test_function = "mpi_core_mla"
     test_name = "mbedtls_mpi_core_mla"
-    unique_combinations_only = False
 
     input_values = [
         "0", "1", "fffe", "ffffffff", "100000000", "20000000000000",
diff --git a/tests/scripts/generate_bignum_tests.py b/tests/scripts/generate_bignum_tests.py
index 89d0ac29e0..c3058e98a9 100755
--- a/tests/scripts/generate_bignum_tests.py
+++ b/tests/scripts/generate_bignum_tests.py
@@ -78,6 +78,7 @@ class BignumOperation(bignum_common.OperationCommon, BignumTarget,
                       metaclass=ABCMeta):
     #pylint: disable=abstract-method
     """Common features for bignum operations in legacy tests."""
+    unique_combinations_only = True
     input_values = [
         "", "0", "-", "-0",
         "7b", "-7b",