diff --git a/lib/sysgeneral.py b/lib/sysgeneral.py
index edc094b..58ea5b5 100644
--- a/lib/sysgeneral.py
+++ b/lib/sysgeneral.py
@@ -59,7 +59,11 @@ class SysGeneral:
                 readable_hash = hashlib.sha256(downloaded_content).hexdigest()
                 if expected_hash == readable_hash:
                     return
-                raise Exception("Checksum mismatch")
+                raise Exception(f"Checksum mismatch for file {os.path.basename(file_name)}:\n\
+expected: {expected_hash}\n\
+actual:   {readable_hash}\n\
+When in doubt, try deleting the file in question -- it will be downloaded again when running \
+this script the next time")
 
         raise Exception("File checksum is not yet recorded")
 
diff --git a/sysa/mes/mes.kaem b/sysa/mes/mes.kaem
index 55eb17c..ac7e523 100755
--- a/sysa/mes/mes.kaem
+++ b/sysa/mes/mes.kaem
@@ -40,7 +40,7 @@ chmod 755 ${bindir}/mes-m2
 
 # Build Mes C library using mes-m2 bootstrapped Mes
 
-alias mescc="${MES} --no-auto-compile -e main ${bindir}/mescc.scm -- -D HAVE_CONFIG_H=1 -I include -I include/linux/x86 -c"
+alias mescc="${MES} -e main ${bindir}/mescc.scm -D HAVE_CONFIG_H=1 -I include -I include/linux/x86 -c"
 
 # Start with crt1.o
 mescc lib/linux/x86-mes-mescc/crt1.c