diff --git a/tests/include/test/bignum_codepath_check.h b/tests/include/test/bignum_codepath_check.h
index 2f954e9..3d72be1 100644
--- a/tests/include/test/bignum_codepath_check.h
+++ b/tests/include/test/bignum_codepath_check.h
@@ -6,8 +6,8 @@
  *      - MBEDTLS_MPI_IS_SECRET: Only safe paths were teken since the last reset
  *      - MBEDTLS_MPI_IS_PUBLIC: At least one unsafe path has been taken since the last reset
  *
- * Using a simple global variable to track execution path. Making it work with multithreading
- * doesn't worth the effort as multithreaded tests add little to no value here.
+ * Use a simple global variable to track execution path. Making it work with multithreading
+ * isn't worth the effort as multithreaded tests add little to no value here.
  */
 /*
  *  Copyright The Mbed TLS Contributors
@@ -47,7 +47,7 @@
  *
  * When a function returns with an error, it can do so before reaching any interesting codepath. The
  * same can happen if a parameter to the function is zero. In these cases we need to allow
- * uninitialised value for the codepath tracking variable.
+ * the codepath tracking variable to still have its initial "not set" value.
  *
  * This macro expands to an instruction, not an expression.
  * It may jump to the \c exit label.
@@ -70,7 +70,8 @@
 /** Check the codepath taken and fail if it doesn't match.
  *
  * When a function returns with an error, it can do so before reaching any interesting codepath. In
- * this case we need to allow uninitialised value for the codepath tracking variable.
+ * this case we need to allow the codepath tracking variable to still have its
+ * initial "not set" value.
  *
  * This macro expands to an instruction, not an expression.
  * It may jump to the \c exit label.
diff --git a/tf-psa-crypto/drivers/builtin/src/bignum_core.h b/tf-psa-crypto/drivers/builtin/src/bignum_core.h
index da75546..484fa8c 100644
--- a/tf-psa-crypto/drivers/builtin/src/bignum_core.h
+++ b/tf-psa-crypto/drivers/builtin/src/bignum_core.h
@@ -104,7 +104,7 @@
  *  } else {
  *      // safe path
  *  }
- * not the other way round, in order to prevent misuse. (This is, if a value
+ * not the other way round, in order to prevent misuse. (That is, if a value
  * other than the two below is passed, default to the safe path.)
  *
  * The value of MBEDTLS_MPI_IS_PUBLIC is chosen in a way that is unlikely to happen by accident, but