1 files changed, 6 insertions, 0 deletions
diff --git a/tools/gbdemo b/tools/gbdemo
index e2b8e13..956c9f3 100755
--- a/tools/gbdemo
+++ b/tools/gbdemo
@@ -130,6 +130,12 @@ def hub_type(payload: bytes):
 def v_spawn(args):
     nohub = "--nohub" in args          # offline: no link (script smoke-tests)
     args = [a for a in args if a != "--nohub"]
+    # bare --bios: resolve the emulator's default boot ROM to an absolute path
+    # (the tmux pane's cwd is wherever the user happens to be)
+    if "--bios" in args:
+        i = args.index("--bios")
+        if i + 1 >= len(args) or args[i + 1].startswith("-"):
+            args.insert(i + 1, os.path.join(GBC, "bios/gbc_bios.bin"))
     if not nohub and not os.path.exists(HUB):
         die("no hub at %s - start it first: sudo tools/gbhub --daemon" % HUB)
     rom = "/tmp/gbdemo_%d.gb" % os.getpid()   # private copy: no .sav clashes