1 files changed, 69 insertions, 0 deletions

diff --git a/pad_for_optiplex.py b/pad_for_optiplex.py
new file mode 100644
index 0000000..2d48552
--- /dev/null
+++ b/pad_for_optiplex.py
@@ -0,0 +1,69 @@
+#!/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)