ui: save screen after refresh, if env var is set

src/trezor/ui/__init__.py

@@ -13,6 +13,8 @@ if __debug__:
     def debug_display_refresh():
         display.bar(Display.WIDTH - 8, 0, 8, 8, 0xF800)
         display.refresh()
+        if utils.SAVE_SCREEN:
+            display.save("refresh")
 
     loop.after_step_hook = debug_display_refresh
 

src/trezor/utils.py

@@ -13,6 +13,16 @@ from trezorutils import (  # noqa: F401
     set_mode_unprivileged,
 )
 
+if __debug__:
+    if EMULATOR:
+        import uos
+
+        TEST = int(uos.getenv("TREZOR_TEST") or "0")
+        SAVE_SCREEN = int(uos.getenv("TREZOR_SAVE_SCREEN") or "0")
+    else:
+        TEST = 0
+        SAVE_SCREEN = 0
+
 
 def unimport_begin():
     return set(sys.modules)