From 1e249c2d47238665f49bdeb124f7f8735133f039 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 15 Jun 2023 08:06:15 +0530
Subject: [PATCH] MOBI Input: Ignore another form of corruption in trailing
 bytes. Fixes #2023943 [Private
 bug](https://bugs.launchpad.net/calibre/+bug/2023943)

---
 src/calibre/ebooks/mobi/reader/mobi6.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/calibre/ebooks/mobi/reader/mobi6.py b/src/calibre/ebooks/mobi/reader/mobi6.py
index f3bb969272..de1f42f102 100644
--- a/src/calibre/ebooks/mobi/reader/mobi6.py
+++ b/src/calibre/ebooks/mobi/reader/mobi6.py
@@ -788,7 +788,10 @@ class MobiReader:
             flags >>= 1
         if self.book_header.extra_flags & 1:
             off = size - num - 1
-            num += (ord(data[off:off+1]) & 0x3) + 1
+            try:
+                num += (ord(data[off:off+1]) & 0x3) + 1
+            except TypeError:
+                num += 1
         return num
 
     def warn_about_trailing_entry_corruption(self):