diff --git a/ggml/src/ggml-quants.c b/ggml/src/ggml-quants.c
index 20a9831b..f7c83bed 100644
--- a/ggml/src/ggml-quants.c
+++ b/ggml/src/ggml-quants.c
@@ -1971,7 +1971,7 @@ static float make_qkx2_quants(int n, int nmax, const float * restrict x, const f
         sum_x += w * x[i];
     }
     if (min > 0) min = 0;
-    if (max == min) {
+    if (max - min < 1e-10f) {
         for (int i = 0; i < n; ++i) L[i] = 0;
         *the_min = -min;
         return 0.f;
@@ -2218,7 +2218,7 @@ static float make_qkx3_quants(int n, int nmax, const float * restrict x, const f
     if (min > 0) {
         min = 0;
     }
-    if (max <= min) {
+    if (max - min < 1e-10f) {
         memset(L, 0, n);
         *the_min = -min;
         return 0.f;
@@ -2340,7 +2340,7 @@ static float make_qp_quants(int n, int nmax, const float * restrict x, uint8_t *
     for (int i = 0; i < n; ++i) {
         max = MAX(max, x[i]);
     }
-    if (!max) { // all zero
+    if (max < 1e-16f) { // all zero
         for (int i = 0; i < n; ++i) { L[i] = 0; }
         return 0.f;
     }
@@ -2733,6 +2733,10 @@ void quantize_row_q4_K_ref(const float * restrict x, block_q4_K * restrict y, in
             float av_x = sqrtf(sum_x2/32);
             for (int l = 0; l < 32; ++l) weights[l] = av_x + fabsf(x[32*j + l]);
             scales[j] = make_qkx2_quants(32, 15, x + 32*j, weights, L + 32*j, &mins[j], Laux, -1.f, 0.1f, 20, false);
+            if (isnan(scales[j])) {
+                printf("Oops: NaN scale\n");
+                GGML_ABORT("Fatal error");
+            }
             float scale = scales[j];
             if (scale > max_scale) {
                 max_scale = scale;
@@ -2846,10 +2850,18 @@ static void quantize_row_q4_K_impl(const float * restrict x, block_q4_K * restri
             for (int l = 0; l < 32; ++l) sumw += weights[l];
             sw[j] = sumw;
             scales[j] = make_qkx3_quants(32, 15, x + 32*j, weights, L + 32*j, &mins[j], Laux, -0.9f, 0.05f, 36, false);
+            if (isnan(scales[j])) {
+                printf("%s: got NaN scale\n", __func__);
+                GGML_ABORT("Fatal error");
+            }
         }
 
         float d_block = make_qp_quants(QK_K/32, 63, scales, Ls, sw);
         float m_block = make_qp_quants(QK_K/32, 63, mins,   Lm, sw);
+        if (isnan(d_block) || isnan(m_block)) {
+            printf("%s: d_block = %g, m_block = %g\n", __func__, (double)d_block, (double)m_block);
+            GGML_ABORT("Fatal error");
+        }
         for (int j = 0; j < QK_K/32; ++j) {
             uint8_t ls = Ls[j];
             uint8_t lm = Lm[j];