add message about successful master seed recovery when trying to use master as tmp

(cherry picked from commit ac761c23d5)

releases/Next-ChangeLog.md

@@ -7,6 +7,8 @@ This lists the new changes that have not yet been published in a normal release.
 - Enhancement: Hide Secure Notes & Passwords in Deltamode. Wipe seed if notes menu accessed. 
 - Enhancement: Hide Seed Vault in Deltamode. Wipe seed if Seed Vault menu accessed. 
 - Enhancement: Ability to switch between BIP-32 XPUB and SLIP-132 garbage in `Export XPUB`
+- Enhancement: Use the fact that master seed cannot be used as ephemeral and add UX message 
+  for successful master seed verification.
 - Bugfix: Sometimes see a struck screen after _Verifying..._ in boot up sequence.
   On Q, result is blank screen, on Mk4, result is three-dots screen.
 - Bugfix: Do not allow to enable/disable Seed Vault feature when in temporary seed mode
@@ -17,7 +19,6 @@ This lists the new changes that have not yet been published in a normal release.
 - Change: Testnet3 -> Testnet4 (all parameters are the same)
 
 
-
 # Mk4 Specific Changes
 
 ## 5.4.1 - 2024-??-??

shared/pincodes.py

@@ -473,6 +473,7 @@ class PinAttempt:
     def tmp_secret(self, encoded, chain=None, bip39pw=''):
         # Use indicated secret and stop using the SE; operate like this until reboot
         from glob import settings
+        from utils import xfp2str
         from nvstore import SettingsObject
 
         val = bytes(encoded + bytes(AE_SECRET_LEN - len(encoded)))
@@ -483,7 +484,9 @@ class PinAttempt:
         target_nvram_key = None
         if encoded is not None:
             # disallow using master seed as temporary
-            master_err = "Cannot use master seed as temporary."
+            xfp = xfp2str(settings.master_get("xfp", 0))
+            master_err = ("Cannot use master seed as temporary. BUT you have just successfully "
+                          "tested recovery of your master seed [%s].") % xfp
             target_nvram_key = settings.hash_key(val)
             if SettingsObject.master_nvram_key:
                 assert self.tmp_value

testing/test_ephemeral.py

@@ -1405,6 +1405,7 @@ def test_import_master_as_tmp(reset_seed_words, goto_eph_seed_menu, cap_story,
     title, story = cap_story()
     assert "FAILED" == title
     assert 'Cannot use master seed as temporary.' in story
+    assert 'tested recovery of your master seed' in story
     press_cancel()
 
     # go to ephemeral seed and then try to create new ephemeral seed from master
@@ -1433,6 +1434,7 @@ def test_import_master_as_tmp(reset_seed_words, goto_eph_seed_menu, cap_story,
     title, story = cap_story()
     assert "FAILED" == title
     assert 'Cannot use master seed as temporary.' in story
+    assert 'tested recovery of your master seed' in story
     press_cancel()
 
     # now import same seed but represented as master extended key