KF8 Output: Write useless FLIS/FCIS records as older kindles refuse to open joint MOBI files without them

src/calibre/ebooks/mobi/writer2/main.py

@@ -25,6 +25,15 @@ from calibre.ebooks.mobi.writer2.indexer import Indexer
 WRITE_UNCROSSABLE_BREAKS = False
 NULL_INDEX = 0xffffffff
 
+FLIS = (b'FLIS\0\0\0\x08\0\x41\0\0\0\0\0\0\xff\xff\xff\xff\0\x01\0\x03\0\0\0\x03\0\0\0\x01'+
+            b'\xff'*4)
+
+def fcis(text_length):
+    fcis = b'FCIS\x00\x00\x00\x14\x00\x00\x00\x10\x00\x00\x00\x01\x00\x00\x00\x00'
+    fcis += pack(b'>I', text_length)
+    fcis += b'\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x08\x00\x01\x00\x01\x00\x00\x00\x00'
+    return fcis
+
 class MobiWriter(object):
 
     def __init__(self, opts, resources, kf8, write_page_breaks_after_item=True):
@@ -208,14 +217,9 @@ class MobiWriter(object):
 
         # FCIS/FLIS (Seems to serve no purpose)
         flis_number = len(self.records)
-        self.records.append(
+        self.records.append(FLIS)
-            b'FLIS\0\0\0\x08\0\x41\0\0\0\0\0\0\xff\xff\xff\xff\0\x01\0\x03\0\0\0\x03\0\0\0\x01'+
-            b'\xff'*4)
-        fcis = b'FCIS\x00\x00\x00\x14\x00\x00\x00\x10\x00\x00\x00\x01\x00\x00\x00\x00'
-        fcis += pack(b'>I', self.text_length)
-        fcis += b'\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x08\x00\x01\x00\x01\x00\x00\x00\x00'
         fcis_number = len(self.records)
-        self.records.append(fcis)
+        self.records.append(fcis(self.text_length))
 
         # EOF record
         self.records.append(b'\xE9\x8E\x0D\x0A')
@@ -379,6 +383,12 @@ class MobiWriter(object):
             self.resources.serialize(self.records, used_images)
         resource_record_count = len(self.records) - old
 
+        # FCIS/FLIS (Seems to serve no purpose)
+        flis_number = len(self.records)
+        self.records.append(FLIS)
+        fcis_number = len(self.records)
+        self.records.append(fcis(self.text_length))
+
         # Insert KF8 records
         self.records.append(b'BOUNDARY')
         kf8_header_index = len(self.records)
@@ -398,6 +408,8 @@ class MobiWriter(object):
         header_fields['exth_flags'] = 0b100001010000 # Kinglegen uses this
         header_fields['fdst_record'] = NULL_INDEX
         header_fields['fdst_count'] = 1 # Why not 0? Kindlegen uses 1
+        header_fields['flis_record'] = flis_number
+        header_fields['fcis_record'] = fcis_number
         extra_data_flags = 0b1 # Has multibyte overlap bytes
         if self.primary_index_record_idx is not None:
             extra_data_flags |= 0b10

src/calibre/ebooks/mobi/writer8/mobi.py

@@ -18,6 +18,14 @@ from calibre.ebooks.mobi.writer8.exth import build_exth
 from calibre.utils.filenames import ascii_filename
 
 NULL_INDEX = 0xffffffff
+FLIS = b'FLIS\0\0\0\x08\0\x41\0\0\0\0\0\0\xff\xff\xff\xff\0\x01\0\x03\0\0\0\x03\0\0\0\x01'+ b'\xff'*4
+
+def fcis(text_length):
+    fcis = b'FCIS\x00\x00\x00\x14\x00\x00\x00\x10\x00\x00\x00\x02\x00\x00\x00\x00'
+    fcis += pack(b'>L', text_length)
+    fcis += b'\x00\x00\x00\x00\x00\x00\x00\x28\x00\x00\x00\x00\x00\x00\x00'
+    fcis += b'\x28\x00\x00\x00\x08\x00\x01\x00\x01\x00\x00\x00\x00'
+    return fcis
 
 class MOBIHeader(Header): # {{{
     '''
@@ -115,7 +123,10 @@ class MOBIHeader(Header): # {{{
     exth_flags = DYN
 
     # 132: Unknown
-    unknown = zeroes(36)
+    unknown = zeroes(32)
+
+    # 164: Unknown
+    unknown_index = NULL
 
     # 168: DRM
     drm_offset = NULL
@@ -130,13 +141,13 @@ class MOBIHeader(Header): # {{{
     fdst_record = DYN
     fdst_count = DYN
 
-    # 200: FCI
+    # 200: FCIS
-    fcis_record = NULL
+    fcis_record = DYN
-    fcis_count
+    fcis_count = 1
 
     # 208: FLIS
-    flis_record = NULL
+    flis_record = DYN
-    flis_count
+    flis_count = 1
 
     # 216: Unknown
     unknown3 = zeroes(8)
@@ -193,7 +204,7 @@ HEADER_FIELDS = {'compression', 'text_length', 'last_text_record', 'book_type',
                     'first_resource_record', 'exth_flags', 'fdst_record',
                     'fdst_count', 'ncx_index', 'chunk_index', 'skel_index',
                     'guide_index', 'exth', 'full_title', 'extra_data_flags',
-                    'uid'}
+                    'flis_record', 'fcis_record', 'uid'}
 
 class KF8Book(object):
 
@@ -241,6 +252,12 @@ class KF8Book(object):
         self.fdst_record = len(self.records)
         self.records.extend(writer.fdst_records)
 
+        # FLIS/FCIS
+        self.flis_record = len(self.records)
+        self.records.append(FLIS)
+        self.fcis_record = len(self.records)
+        self.records.append(fcis(self.text_length))
+
         # EOF
         self.records.append(b'\xe9\x8e\r\n') # EOF record