diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 36a8efaae5..779f594dca 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -790,8 +790,8 @@ static void ecjpake_do_round( psa_algorithm_t alg, unsigned int primitive,
 
             if( inject_error == 1 )
             {
-                buffer0[s_x1_pk_off + 8] >>= 4;
-                buffer0[s_x2_pk_off + 7] <<= 4;
+                buffer0[s_x1_pr_off + 8] ^= 1;
+                buffer0[s_x2_pr_off + 7] ^= 1;
                 expected_status = PSA_ERROR_DATA_INVALID;
             }
 
@@ -1013,8 +1013,8 @@ static void ecjpake_do_round( psa_algorithm_t alg, unsigned int primitive,
 
             if( inject_error == 2 )
             {
-                buffer1[c_x1_pk_off + 12] >>= 4;
-                buffer1[c_x2_pk_off + 7] <<= 4;
+                buffer1[c_x1_pr_off + 12] ^= 1;
+                buffer1[c_x2_pr_off + 7] ^= 1;
                 expected_status = PSA_ERROR_DATA_INVALID;
             }