diff --git a/gguf-py/gguf/quants.py b/gguf-py/gguf/quants.py
index 861e87daa..8feec2958 100644
--- a/gguf-py/gguf/quants.py
+++ b/gguf-py/gguf/quants.py
@@ -27,11 +27,11 @@ def quant_shape_from_byte_shape(shape: Sequence[int], quant_type: GGMLQuantizati
 def __compute_fp32_to_bf16(n: np.ndarray) -> np.ndarray:
     n = n.astype(np.float32, copy=False).view(np.uint32)
     # force nan to quiet
-    n = np.where((n & 0x7fffffff) > 0x7f800000, (n & np.uint32(0xffff0000)) | (64 << 16), n)
+    n = np.where((n & 0x7fffffff) > 0x7f800000, (n & np.uint32(0xffff0000)) | np.uint32(64 << 16), n)
     # flush subnormals to zero
     n = np.where((n & 0x7f800000) == 0, n & np.uint32(0x80000000), n)
     # round to nearest even
-    n = (n + (0x7fff + ((n >> 16) & 1))) >> 16
+    n = (np.uint64(n) + (0x7fff + ((n >> 16) & 1))) >> 16
     return n.astype(np.uint16)