diff --git a/.dockerignore b/.dockerignore
index faa1253..9e12941 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -2,7 +2,7 @@
 fonts/**/*
 images/*
 .git
-!fonts/fira/distr/otf/*
+!fonts/fira/distr/ttf/*
 !fonts/hack/build/ttf/*
 !fonts/jetbrainsmono/ttf/*
-!fonts/fira/showcases/*
+!fonts/fira/extras/*
diff --git a/Dockerfile b/Dockerfile
index 82acc0a..2b8dfe7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,4 +6,6 @@ COPY . ./
 
 RUN mkdir -p fonts/output
 
+ENV PYTHONFAULTHANDLER=1
+
 ENTRYPOINT ["make"]
diff --git a/Makefile b/Makefile
index c820bca..d134294 100644
--- a/Makefile
+++ b/Makefile
@@ -4,4 +4,4 @@
 all:
 	fontforge -lang=py -script build.py 2>&1 \
 	| fgrep -v 'This contextual rule applies no lookups.' \
-	| fgrep -v 'Bad device table'
+	| fgrep -v 'Bad device table'
\ No newline at end of file
diff --git a/build.py b/build.py
index 3fe0cce..d56cb44 100644
--- a/build.py
+++ b/build.py
@@ -3,6 +3,7 @@
 import sys
 from glob import glob
 from ligaturize import ligaturize_font
+import fontforge
 
 # Rebuild script for ligaturized fonts.
 # Uses ligaturize.py to do the heavy lifting; this file basically just contains
@@ -23,6 +24,17 @@
 # effectively disable this feature.
 SCALE_LIGATURE_THRESHOLD = 0.044
 
+# Generate fira otf from ttf files
+fira_ttf_list = glob('fonts/fira/distr/ttf/*')
+
+if not fira_ttf_list:
+    print("Error: pattern '%s' didn't match any fira fonts." % fira_ttf_list)
+    sys.exit(1)
+
+for fira_ttf in fira_ttf_list:
+    font = fontforge.open(fira_ttf)
+    print(fira_ttf.replace('.ttf', '.otf'))
+    font.generate(fira_ttf.replace('.ttf', '.otf'))
 
 # Fonts that will be ligaturized. ####
 # Don't put fonts licensed under UFL here, and don't put fonts licensed under
@@ -32,28 +44,28 @@
     {
         'input': 'fonts/hack/build/ttf/Hack-Regular.ttf',
         'ligatures': [
-            'fonts/fira/distr/otf/FiraCode-Regular.otf',
+            'fonts/fira/distr/ttf/FiraCode-Regular.otf',
             'fonts/jetbrainsmono/ttf/JetBrainsMono-Regular.ttf'
         ]
     },
     {
         'input': 'fonts/hack/build/ttf/Hack-Bold.ttf',
         'ligatures': [
-            'fonts/fira/distr/otf/FiraCode-Bold.otf',
+            'fonts/fira/distr/ttf/FiraCode-Bold.otf',
             'fonts/jetbrainsmono/ttf/JetBrainsMono-Bold.ttf'
         ]
     },
     {
         'input': 'fonts/hack/build/ttf/Hack-BoldItalic.ttf',
         'ligatures': [
-            'fonts/fira/distr/otf/FiraCode-Bold.otf',
+            'fonts/fira/distr/ttf/FiraCode-Bold.otf',
             'fonts/jetbrainsmono/ttf/JetBrainsMono-Bold-Italic.ttf'
         ]
     },
     {
         'input': 'fonts/hack/build/ttf/Hack-Italic.ttf',
         'ligatures': [
-            'fonts/fira/distr/otf/FiraCode-Regular.otf',
+            'fonts/fira/distr/ttf/FiraCode-Regular.otf',
             'fonts/jetbrainsmono/ttf/JetBrainsMono-Italic.ttf'
         ]
     },
diff --git a/ligatures.py b/ligatures.py
index cac9b83..f89dfc2 100644
--- a/ligatures.py
+++ b/ligatures.py
@@ -14,7 +14,7 @@ def get_ligatures_from_files(files):
             with open(file, 'r') as f:
                 for line in f:
                     lines.append(line.strip().split(' '))
-        return reduce(list.__add__, lines)
+        return reduce(list.__add__, lines, [])
 
     def is_valid_ligature(ligature):
         # not empty and all chars exist in the dictionary
@@ -40,6 +40,6 @@ def ligature_to_def(ligature):
 
 # 'COPY_CHARACTER_GLYPHS' feature required to prepend the punctuations characters
 ligatures = [{'chars': chars, 'ligature_name': None}] \
-            + create_ligatures_def(pattern ='fonts/fira/showcases/**/showcases.txt')
+            + create_ligatures_def(pattern ='fonts/fira/extras/showcases.txt')
 
 print("Definitions:", ligatures)
diff --git a/ligaturize.py b/ligaturize.py
index 69a0d62..193d17c 100644
--- a/ligaturize.py
+++ b/ligaturize.py
@@ -19,6 +19,8 @@
 def get_copyright(liga_font_family_name):
     switcher = {
         'fira code': 'Programming ligatures added by gaplo917 from FiraCode. Copyright (c) 2015 by Nikita Prokopov',
+        'fira code semibold': 'Programming ligatures added by gaplo917 from FiraCode. Copyright (c) 2015 by Nikita Prokopov',
+        'fira code bold': 'Programming ligatures added by gaplo917 from FiraCode. Copyright (c) 2015 by Nikita Prokopov',
         'jetbrains mono': 'Programming ligatures added by gaplo917 from JetBrains Mono. Copyright (c) 2020 by JetBrains',
     }
     return switcher.get(liga_font_family_name.lower())