diff --git a/core/wasm_shims/tooldata/tooldata_probe_main.cc b/core/wasm_shims/tooldata/tooldata_probe_main.cc
index 506aa70..3e36a66 100644
--- a/core/wasm_shims/tooldata/tooldata_probe_main.cc
+++ b/core/wasm_shims/tooldata/tooldata_probe_main.cc
@@ -84,6 +84,35 @@ int main() {
         return 45;
     }
 
+    const pid_t nonrandom_t0_child = fork();
+    if (nonrandom_t0_child < 0) {
+        return 64;
+    }
+    if (nonrandom_t0_child == 0) {
+        if (tool_mmap_creator(nullptr, 0) != 0) {
+            _exit(65);
+        }
+        CANON_TOOL_TABLE nonrandom_t0 = tooldata_entry_init();
+        nonrandom_t0.toolno = 0;
+        nonrandom_t0.pocketno = 12;
+        if (tooldata_put(nonrandom_t0, 12) == IDX_FAIL) {
+            _exit(66);
+        }
+        // LinuxCNC src/emc/tooldata/tooldata_mmap.cc returns pocket 0 for T0
+        // before scanning table entries when the toolchanger is not random.
+        if (tooldata_find_index_for_tool(0) != 0) {
+            _exit(67);
+        }
+        _exit(0);
+    }
+    int nonrandom_t0_status = 0;
+    if (waitpid(nonrandom_t0_child, &nonrandom_t0_status, 0) != nonrandom_t0_child) {
+        return 68;
+    }
+    if (!WIFEXITED(nonrandom_t0_status) || WEXITSTATUS(nonrandom_t0_status) != 0) {
+        return 69;
+    }
+
     if (tool_mmap_user() != -1) {
         return 25;
     }