diff --git a/proto-opencl/host.c b/proto-opencl/host.c
index 985495545..563e8d81b 100644
--- a/proto-opencl/host.c
+++ b/proto-opencl/host.c
@@ -273,6 +273,13 @@ static void usage(void) {
 static int isPow2(long long v) { return v > 0 && (v & (v - 1)) == 0; }
 static int log2u32(uint32_t v) { int n = 0; while (v > 1u) { v >>= 1; ++n; } return n; }
 
+/* --flip-leaf-word N (the kit's known-failed case for the fingerprint, class v5): after pf_load_leaves has checked the
+ * pack's leaves, bit 0 of 32-bit word N of the DEVICE copy is flipped before the upload (packLeavesBuffer), so the run
+ * proceeds on a dataset keyed by one wrong leaf word; the dataset self-test must then fail (head, last word or a sample)
+ * and, run through, the fingerprint must differ from the pack's. -1 = off. Declared before parseArgs, which sets it (the
+ * first form sat after it and the kit's C99 build read it undeclared, 8 October 2026). */
+static long gFlipLeafWord = -1;
+
 static Options parseArgs(int argc, char** argv) {
     Options o;
     int i;
@@ -1192,12 +1199,6 @@ static cl_int setBuildArgs(cl_kernel k, cl_mem ds, cl_mem cache, cl_mem leaves,
 /* The leaves of a pack directory as a device buffer (NULL with *nLeaves 0 for a pack of another class): read and checked
  * against the pack's count and FNV-1a 64 by pf_load_leaves before the upload. The caller releases the buffer after the
  * build (the leaves are not needed while hashing). Returns 1, or 0 with err set. */
-/* --flip-leaf-word N (the kit's known-failed case for the fingerprint, class v5): after pf_load_leaves has checked the
- * pack's leaves, bit 0 of 32-bit word N of the DEVICE copy is flipped before the upload, so the run proceeds on a dataset
- * keyed by one wrong leaf word; the dataset self-test must then fail (head, last word or a sample) and, run through, the
- * fingerprint must differ from the pack's. -1 = off. */
-static long gFlipLeafWord = -1;
-
 static int packLeavesBuffer(Device* dv, const char* packDir, cl_mem* leaves, cl_uint* nLeaves, char* err, size_t errCap) {
     PfPack pk;
     char perr[700];