From 6450173e19d93547f4e67a345df0b8c262ad6efc Mon Sep 17 00:00:00 2001
From: user <user@clank>
Date: Sat, 18 Jul 2026 22:11:07 +0200
Subject: demo: boot through the CGB BIOS + double-speed ROM in the README gif

spawn --bios shows the real power-on show (logo drop + splash) before
gbos boots; gbdemo resolves a bare --bios to the emulator's bundled
boot ROM by absolute path (the tmux pane cwd is wherever the user is).
The screen-synced waitfor absorbs the extra ~4s - only the first
prompt timeout got a bump. Regenerated with the double-speed kernel:
same demo, boots and scrolls visibly snappier.
---
 demo/gbos-demo.gif | Bin 350160 -> 330712 bytes
 demo/readme.gbd    |   7 ++++---
 tools/gbdemo       |   6 ++++++
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/demo/gbos-demo.gif b/demo/gbos-demo.gif
index 754477d..c5208f7 100644
Binary files a/demo/gbos-demo.gif and b/demo/gbos-demo.gif differ
diff --git a/demo/readme.gbd b/demo/readme.gbd
index 1f2c09f..21a9667 100644
--- a/demo/readme.gbd
+++ b/demo/readme.gbd
@@ -7,11 +7,12 @@
 # Every waitfor syncs on REAL screen text (the terminal's WRAM shadow), so
 # boot, DHCP and IRC-server timing can vary without breaking the choreography.
 
-spawn --chrome
+# --bios: boot through the real CGB boot ROM (logo drop + chime + splash)
+spawn --chrome --bios
 record /tmp/gbos-demo.gbv 2
 
-# cold boot: kernel dmesg, netd grabs a DHCP lease, then the shell prompt
-waitfor "/# " 60
+# BIOS animation (~4s), then cold boot: dmesg, DHCP lease, shell prompt
+waitfor "/# " 90
 wait 2
 
 slowtype uname -a
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
-- 
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