diff --git a/core/src/apps/webauthn/__init__.py b/core/src/apps/webauthn/__init__.py
index b1c3637d05..3f72e26ad5 100644
--- a/core/src/apps/webauthn/__init__.py
+++ b/core/src/apps/webauthn/__init__.py
@@ -1,6 +1,6 @@
-def boot() -> None:
+def boot(mutex) -> None:
     from trezor import loop
     import usb
     from .fido2 import handle_reports
 
-    loop.schedule(handle_reports(usb.iface_webauthn))
+    loop.schedule(handle_reports(usb.iface_webauthn, mutex))
diff --git a/core/src/apps/webauthn/fido2.py b/core/src/apps/webauthn/fido2.py
index 8e0f64fb50..5c1ee4c4da 100644
--- a/core/src/apps/webauthn/fido2.py
+++ b/core/src/apps/webauthn/fido2.py
@@ -538,7 +538,7 @@ def send_cmd_sync(cmd: Cmd, iface: HID) -> None:
         seq += 1
 
 
-async def handle_reports(iface: HID) -> None:
+async def handle_reports(iface: HID, mutex) -> None:
     dialog_mgr = DialogManager(iface)
 
     while True:
@@ -546,10 +546,14 @@ async def handle_reports(iface: HID) -> None:
             req = await _read_cmd(iface)
             if req is None:
                 continue
-            if not dialog_mgr.allow_cid(req.cid):
+            if mutex is not None and mutex.get_busy(iface.iface_num()):
                 resp: Cmd | None = cmd_error(req.cid, _ERR_CHANNEL_BUSY)
             else:
-                resp = _dispatch_cmd(req, dialog_mgr)
+                mutex.set_busy(iface.iface_num())
+                if not dialog_mgr.allow_cid(req.cid):
+                    resp: Cmd | None = cmd_error(req.cid, _ERR_CHANNEL_BUSY)
+                else:
+                    resp = _dispatch_cmd(req, dialog_mgr)
             if resp is not None:
                 await send_cmd(resp, iface)
         except Exception as e:
diff --git a/core/src/session.py b/core/src/session.py
index 9777905866..b96c938eab 100644
--- a/core/src/session.py
+++ b/core/src/session.py
@@ -7,10 +7,12 @@ import usb
 
 apps.base.boot()
 
+mutex = Mutex()
+
 if not utils.BITCOIN_ONLY and usb.ENABLE_IFACE_WEBAUTHN:
     import apps.webauthn
 
-    apps.webauthn.boot()
+    apps.webauthn.boot(mutex)
 
 if __debug__:
     import apps.debug
@@ -22,8 +24,6 @@ apps.base.set_homescreen()
 workflow.start_default()
 
 
-mutex = Mutex()
-
 mutex.add(usb.iface_wire.iface_num())
 mutex.add(usb.iface_debug.iface_num())