diff --git a/src/neogb/la_ff_16.c b/src/neogb/la_ff_16.c
index 7cbd7a7b..de7ba538 100644
--- a/src/neogb/la_ff_16.c
+++ b/src/neogb/la_ff_16.c
@@ -778,7 +778,9 @@ static void probabilistic_sparse_reduced_echelon_form_ff_16(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -1675,7 +1677,9 @@ static cf16_t **probabilistic_dense_linear_algebra_ff_16(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -1807,7 +1811,9 @@ static cf16_t **probabilistic_sparse_dense_echelon_form_ff_16(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
diff --git a/src/neogb/la_ff_32.c b/src/neogb/la_ff_32.c
index 90953f21..c5794cf8 100644
--- a/src/neogb/la_ff_32.c
+++ b/src/neogb/la_ff_32.c
@@ -186,7 +186,9 @@ static int is_kernel_trivial(
 
     /* fill random value array */
     for (i = 0; i < ncr; ++i) {
-        mul[i]  = (int64_t)rand() & fc;
+        do {
+            mull[j] = (int64_t)rand() & fc;
+        } while (mull[j] == 0);
     }
     for (i = 0; i < sat->ld; ++i) {
         memset(dr, 0, (uint64_t)dim * sizeof(int64_t));
@@ -2382,7 +2384,9 @@ static void probabilistic_sparse_reduced_echelon_form_ff_32(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() & mask;
+                    do {
+                        mull[j] = (int64_t)rand() & mask;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -3599,7 +3603,9 @@ static cf32_t **probabilistic_dense_linear_algebra_ff_32(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() & mask;
+                    do {
+                        mull[j] = (int64_t)rand() & mask;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -3731,7 +3737,9 @@ static cf32_t **probabilistic_sparse_dense_echelon_form_ff_32(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
diff --git a/src/neogb/la_ff_8.c b/src/neogb/la_ff_8.c
index ef38c4cb..2f740081 100644
--- a/src/neogb/la_ff_8.c
+++ b/src/neogb/la_ff_8.c
@@ -927,7 +927,9 @@ static void probabilistic_sparse_reduced_echelon_form_ff_8(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -1804,7 +1806,9 @@ static cf8_t **probabilistic_dense_linear_algebra_ff_8(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */
@@ -1936,7 +1940,9 @@ static cf8_t **probabilistic_sparse_dense_echelon_form_ff_8(
 
                 /* fill random value array */
                 for (j = 0; j < nrbl; ++j) {
-                    mull[j] = (int64_t)rand() % fc;
+                    do {
+                        mull[j] = (int64_t)rand() & fc;
+                    } while (mull[j] == 0);
                 }
                 /* generate one dense row as random linear combination
                  * of the rows of the block */