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#!/usr/bin/env python3
"""pad_for_optiplex.py — pad a UEFI bootloader PE for Optiplex 7010
The Optiplex 7010 AMI Aptio firmware rejects PEs smaller than ~160KB
("no bootable devices"). This pads the PE to match systemd-boot's size
and sets SizeOfImage accordingly.
"""
import struct, sys, os
def pad(path):
try:
with open(path, 'rb') as f:
d = bytearray(f.read())
except IOError as e:
print(f" ERROR: cannot read {path}: {e}")
return False
po = struct.unpack('<I', d[0x3C:0x40])[0]
if d[po:po+4] != b'PE\x00\x00':
print(f" Not a PE file")
return False
opt = po + 24
# Target size: 160256 bytes (matching systemd-boot)
target = 160256
if len(d) >= target:
print(f" Already >= {target} bytes ({len(d)}), nothing to do")
return True
# Compute SizeOfImage: round current SizeOfImage to match file growth
cur_si = struct.unpack('<I', d[opt+56:opt+60])[0]
cur_file_size = len(d)
# The file is padded after all sections. SizeOfImage is the highest
# RVA + virtual size, rounded up to SectionAlignment. After padding
# the file, we need to increase SizeOfImage so the firmware sees a
# consistent image.
#
# Simple approach: set SizeOfImage = target - file_delta + old_si
# Actually: SizeOfImage already covers our sections at up to ~0x4000.
# We just need to make it large enough for the padded region.
# Use systemd-boot's SizeOfImage = 0x2d000 as reference.
file_growth = target - len(d)
new_si = ((cur_si + file_growth + 0xfff) // 0x1000) * 0x1000
# Pad the file
d += b'\x00' * file_growth
# Update SizeOfImage in optional header
struct.pack_into('<I', d, opt+56, new_si)
try:
with open(path, 'wb') as f:
f.write(d)
except IOError as e:
print(f" ERROR: cannot write {path}: {e}")
return False
print(f" Padded: {len(d)} bytes (was {cur_file_size}), SizeOfImage = {new_si:#x}")
return True
if __name__ == '__main__':
if len(sys.argv) < 2:
print(f"Usage: {sys.argv[0]} <pe-path>")
sys.exit(1)
if not pad(sys.argv[1]):
sys.exit(1)
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