Record headset results for sideloading and devkit pairing

Tested on a Frame (BUILD_ID 20260922.6101926):

- Devkit pairing: the service runs and answers properties.json, but /register
  refuses with "please put the Steam client in pairing mode" unless Steam is on
  Settings > Developer > Pair new host. Both setup paths now say so and keep
  asking for 2 minutes before falling back to the password.
- Sideloading: registering, launching, quoted start paths and Remove work; a
  Windows exe runs under Proton 11 through FEX. An aarch64 build starts but
  outside the runtime container, and an x86-64 Linux build doesn't start
  because the x86-64 Steam Linux Runtime 4.0 isn't installed. The inspect note
  for x86-64 Linux builds now says so.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ui/frame_connect.py

@@ -58,11 +58,14 @@ def say(msg):
 # port 32000: GET /properties.json names the user to log in as; POST /register with
 # "ssh-rsa <key> <comment> <magic>" shows an approve prompt in the headset (the
 # comment is what it displays, 30 s to answer), then installs the key and turns sshd on.
+# The prompt only appears while Steam is on Settings > Developer > Pair new host;
+# otherwise /register answers 403 "please put the Steam client in pairing mode".
 
 DEVKIT_PORT = 32000
 DEVKIT_SERVICE = "_steamos-devkit._tcp"
 MAGIC_PHRASE = "900b919520e4cf601998a71eec318fec"  # fixed token Valve's client appends
 REGISTER_TIMEOUT = 60
+PAIRING_MODE_WAIT = 120  # seconds to keep asking while the user opens "Pair new host"
 # A LAN host: never go through an HTTP(S)_PROXY from the environment.
 _opener = urllib.request.build_opener(urllib.request.ProxyHandler({}))
 
@@ -141,8 +144,15 @@ def devkit_pair(host, pub, comment, port=DEVKIT_PORT, on_login=None):
         return f"devkit service not reachable on port {port}: {why(e)}"
     if login and on_login:
         on_login(login)
-    say("    Approve the pairing request in the headset (it waits about 30 seconds)")
-    ok, msg = register(host, register_body(pub, comment), port)
+    say("    In the headset: Steam Settings > Developer > Pair new host, then approve the request")
+    body = register_body(pub, comment)
+    ok, msg = register(host, body, port)
+    # The headset refuses at once unless Steam is on its "Pair new host" screen
+    # (verified on a Frame, 2026-09-26), so keep asking while the user opens it.
+    deadline = time.monotonic() + PAIRING_MODE_WAIT
+    while not ok and "pairing mode" in msg and time.monotonic() < deadline:
+        time.sleep(3)
+        ok, msg = register(host, body, port)
     return None if ok else f"devkit pairing failed: {msg}"
 
 

ui/frame_titles.py

@@ -399,7 +399,9 @@ def runtime_for(target, found=()):
     if fmt == 'elf' and arch == 'arm64':
         return 'SteamLinuxRuntime_4-arm64', 'Native ARM64 Linux build.'
     if fmt == 'elf' and arch == 'x86_64':
-        return 'SteamLinuxRuntime_4', 'x86-64 Linux build: runs through FEX (inferred, not yet checked).'
+        return 'SteamLinuxRuntime_4', ("x86-64 Linux build: probably won't start. It needs the x86-64 Steam "
+                                       "Linux Runtime 4.0, which the Frame didn't install for a sideloaded title "
+                                       "(2026-09-26). Use an ARM64 or Windows build if there is one.")
     raise FrameError(f"{target['path']} is a {arch} Linux program; the Frame runs ARM64 and x86-64 (through FEX) only")