diff --git a/crypto_kem/frodokem640shake/opt/matrix_shake.c b/crypto_kem/frodokem640shake/opt/matrix_shake.c
index cf7f15b4..6b53aaca 100644
--- a/crypto_kem/frodokem640shake/opt/matrix_shake.c
+++ b/crypto_kem/frodokem640shake/opt/matrix_shake.c
@@ -13,8 +13,6 @@
 #include "common.h"
 #include "params.h"
 
-#define USE_SHAKE128_FOR_A 1
-
 int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_as_plus_e(uint16_t *out, const uint16_t *s, const uint16_t *e, const uint8_t *seed_A) {
     // Generate-and-multiply: generate matrix A (N x N) row-wise, multiply by s on the right.
     // Inputs: s, e (N x N_BAR)
@@ -26,28 +24,6 @@ int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_as_plus_e(uint16_t *out, const uint16_t
         *((uint32_t *)&out[i]) = *((uint32_t *)&e[i]);
     }
 
-    #if defined(USE_AES128_FOR_A)
-    int16_t a_row_temp[4 * PARAMS_N] = {0};                     // Take four lines of A at once
-    uint8_t aes_key_schedule[16 * 11];
-    AES128_load_schedule(seed_A, aes_key_schedule);
-
-    for (j = 0; j < PARAMS_N; j += PARAMS_STRIPE_STEP) {
-        a_row_temp[j + 1 + 0 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(j);     // Loading values in the little-endian order
-        a_row_temp[j + 1 + 1 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(j);
-        a_row_temp[j + 1 + 2 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(j);
-        a_row_temp[j + 1 + 3 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(j);
-    }
-
-    for (i = 0; i < PARAMS_N; i += 4) {
-        for (j = 0; j < PARAMS_N; j += PARAMS_STRIPE_STEP) {    // Go through A, four rows at a time
-            a_row_temp[j + 0 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i + 0); // Loading values in the little-endian order
-            a_row_temp[j + 1 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i + 1);
-            a_row_temp[j + 2 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i + 2);
-            a_row_temp[j + 3 * PARAMS_N] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i + 3);
-        }
-
-        AES128_ECB_enc_sch((uint8_t *)a_row_temp, 4 * PARAMS_N * sizeof(int16_t), aes_key_schedule, (uint8_t *)a_row);
-    #elif defined (USE_SHAKE128_FOR_A)
     uint8_t seed_A_separated[2 + BYTES_SEED_A];
     uint16_t *seed_A_origin = (uint16_t *)&seed_A_separated;
     memcpy(&seed_A_separated[2], seed_A, BYTES_SEED_A);
@@ -60,7 +36,6 @@ int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_as_plus_e(uint16_t *out, const uint16_t
         shake128((unsigned char *)(a_row + 2 * PARAMS_N), (unsigned long long)(2 * PARAMS_N), seed_A_separated, 2 + BYTES_SEED_A);
         seed_A_origin[0] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i + 3);
         shake128((unsigned char *)(a_row + 3 * PARAMS_N), (unsigned long long)(2 * PARAMS_N), seed_A_separated, 2 + BYTES_SEED_A);
-    #endif
         for (k = 0; k < 4 * PARAMS_N; k++) {
             a_row[k] = PQCLEAN_FRODOKEM640SHAKE_OPT_LE_TO_UINT16(a_row[k]);
         }
@@ -79,10 +54,6 @@ int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_as_plus_e(uint16_t *out, const uint16_t
             out[(i + 3)*PARAMS_NBAR + k] += sum[3];
         }
     }
-
-    #if defined(USE_AES128_FOR_A)
-    AES128_free_schedule(aes_key_schedule);
-    #endif
     return 1;
 }
 
@@ -99,51 +70,6 @@ int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_sa_plus_e(uint16_t *out, const uint16_t
         *((uint32_t *)&out[i]) = *((uint32_t *)&e[i]);
     }
 
-    #if defined(USE_AES128_FOR_A)
-    int k;
-    uint16_t a_cols[PARAMS_N * PARAMS_STRIPE_STEP] = {0};
-    uint16_t a_cols_t[PARAMS_N * PARAMS_STRIPE_STEP];
-    uint16_t a_cols_temp[PARAMS_N * PARAMS_STRIPE_STEP] = {0};
-    uint8_t aes_key_schedule[16 * 11];
-    AES128_load_schedule(seed_A, aes_key_schedule);
-
-    for (i = 0, j = 0; i < PARAMS_N; i++, j += PARAMS_STRIPE_STEP) {
-        a_cols_temp[j] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(i);                       // Loading values in the little-endian order
-    }
-
-    for (kk = 0; kk < PARAMS_N; kk += PARAMS_STRIPE_STEP) {     // Go through A's columns, 8 (== PARAMS_STRIPE_STEP) columns at a time.
-        for (i = 0; i < (PARAMS_N * PARAMS_STRIPE_STEP); i += PARAMS_STRIPE_STEP) {
-            a_cols_temp[i + 1] = PQCLEAN_FRODOKEM640SHAKE_OPT_UINT16_TO_LE(kk);              // Loading values in the little-endian order
-        }
-
-        AES128_ECB_enc_sch((uint8_t *)a_cols_temp, PARAMS_N * PARAMS_STRIPE_STEP * sizeof(int16_t), aes_key_schedule, (uint8_t *)a_cols);
-
-        for (i = 0; i < PARAMS_N; i++) {                        // Transpose a_cols to have access to it in the column-major order.
-            for (k = 0; k < PARAMS_STRIPE_STEP; k++) {
-                a_cols_t[k * PARAMS_N + i] = PQCLEAN_FRODOKEM640SHAKE_OPT_LE_TO_UINT16(a_cols[i * PARAMS_STRIPE_STEP + k]);
-            }
-        }
-
-        for (i = 0; i < PARAMS_NBAR; i++) {
-            for (k = 0; k < PARAMS_STRIPE_STEP; k += PARAMS_PARALLEL) {
-                uint16_t sum[PARAMS_PARALLEL] = {0};
-                for (j = 0; j < PARAMS_N; j++) {                // Matrix-vector multiplication
-                    uint16_t sp = s[i * PARAMS_N + j];
-                    sum[0] += sp * a_cols_t[(k + 0) * PARAMS_N + j];
-                    sum[1] += sp * a_cols_t[(k + 1) * PARAMS_N + j];
-                    sum[2] += sp * a_cols_t[(k + 2) * PARAMS_N + j];
-                    sum[3] += sp * a_cols_t[(k + 3) * PARAMS_N + j];
-                }
-                out[i * PARAMS_N + kk + k + 0] += sum[0];
-                out[i * PARAMS_N + kk + k + 2] += sum[2];
-                out[i * PARAMS_N + kk + k + 1] += sum[1];
-                out[i * PARAMS_N + kk + k + 3] += sum[3];
-            }
-        }
-    }
-    AES128_free_schedule(aes_key_schedule);
-
-    #elif defined (USE_SHAKE128_FOR_A)  // SHAKE128
     int t = 0;
     uint16_t a_cols[4 * PARAMS_N];
 
@@ -177,7 +103,5 @@ int PQCLEAN_FRODOKEM640SHAKE_OPT_mul_add_sa_plus_e(uint16_t *out, const uint16_t
             }
         }
     }
-    #endif
-
     return 1;
 }