--- qemu/roms/seabios/tools/buildrom.py	2018/04/24 17:36:48	1.1.1.1
+++ qemu/roms/seabios/tools/buildrom.py	2018/04/24 19:44:00	1.1.1.2
@@ -28,6 +28,11 @@ def main():
     data += "\0" * (alignpos(count, 512) - count)
     count = len(data)
 
+    # Check if a pci header is present
+    pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8)
+    if pcidata != 0:
+        data = data[:pcidata + 16] + chr(count/512) + chr(0) + data[pcidata + 18:]
+
     # Fill in size field; clear checksum field
     data = data[:2] + chr(count/512) + data[3:6] + "\0" + data[7:]