diff --git a/f4pga/common_modules/synth.py b/f4pga/common_modules/synth.py
index ece9e7f..fcf12da 100755
--- a/f4pga/common_modules/synth.py
+++ b/f4pga/common_modules/synth.py
@@ -17,7 +17,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-import os
+from os import environ
 from pathlib import Path
 
 from f4pga.common import decompose_depname, get_verbosity_level, sub as common_sub
@@ -44,7 +44,7 @@ def yosys_synth(tcl, tcl_env, verilog_files=[], read_verilog_args=None, log=None
     optional = []
     if log:
         optional += ['-l', log]
-    env = os.environ.copy()
+    env = environ.copy()
     env.update(tcl_env)
 
     tcl = f'tcl {tcl}'
@@ -63,7 +63,7 @@ def yosys_synth(tcl, tcl_env, verilog_files=[], read_verilog_args=None, log=None
 
 def yosys_conv(tcl, tcl_env, synth_json):
     # Set up environment for TCL weirdness
-    env = os.environ.copy()
+    env = environ.copy()
     env.update(tcl_env)
     return common_sub('yosys', '-p', f'read_json {synth_json}; tcl {tcl}', env=env)
 
@@ -76,13 +76,13 @@ class SynthModule(Module):
 
         top = ctx.values.top
         if ctx.takes.build_dir:
-            top = os.path.join(ctx.takes.build_dir, top)
+            top = str(Path(ctx.takes.build_dir) / top)
         mapping['eblif'] = top + '.eblif'
         mapping['fasm_extra'] = top + '_fasm_extra.fasm'
         mapping['json'] = top + '.json'
         mapping['synth_json'] = top + '_io.json'
 
-        b_path = os.path.dirname(top)
+        b_path = Path(top).parent.name
 
         for extra in self.extra_products:
             name, spec = decompose_depname(extra)
@@ -92,9 +92,7 @@ class SynthModule(Module):
                     f'(?) specifier. Product causing this error: `{extra}`.'
                 )
             elif spec == 'req':
-                mapping[name] = \
-                    os.path.join(b_path,
-                                 ctx.values.device + '_' + name + '.' + name)
+                mapping[name] = str(Path(b_path) / f'{ctx.values.device}_{name}.{name}')
 
         return mapping
 
@@ -117,9 +115,9 @@ class SynthModule(Module):
         common_sub('python3', str(split_inouts), '-i', ctx.outputs.json, '-o',
             ctx.outputs.synth_json)
 
-        if not os.path.isfile(ctx.produces.fasm_extra):
-            with open(ctx.produces.fasm_extra, 'w') as f:
-                f.write('')
+        if not Path(ctx.produces.fasm_extra).is_file():
+            with Path(ctx.produces.fasm_extra).open('w') as wfptr:
+                wfptr.write('')
 
         yield f'Converting...'
         yosys_conv(str(conv_tcl), tcl_env, ctx.outputs.synth_json)