51 lines
1.9 KiB
Python
51 lines
1.9 KiB
Python
|
"""
|
||
|
|
mbed SDK
|
||
|
|
Copyright (c) 2011-2013 ARM Limited
|
||
|
|
|
||
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
you may not use this file except in compliance with the License.
|
||
|
|
You may obtain a copy of the License at
|
||
|
|
|
||
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
|
||
|
|
Unless required by applicable law or agreed to in writing, software
|
||
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
See the License for the specific language governing permissions and
|
||
|
|
limitations under the License.
|
||
|
|
|
||
|
|
|
||
|
|
http://www.nxp.com/documents/user_manual/UM10360.pdf
|
||
|
|
|
||
|
|
32.3.1.1 Criterion for Valid User Code
|
||
|
|
The reserved Cortex-M3 exception vector location 7 (offset 0x1C in the vector table)
|
||
|
|
should contain the 2's complement of the check-sum of table entries 0 through 6. This
|
||
|
|
causes the checksum of the first 8 table entries to be 0. The boot loader code checksums
|
||
|
|
the first 8 locations in sector 0 of the flash. If the result is 0, then execution control is
|
||
|
|
transferred to the user code.
|
||
|
|
"""
|
||
|
|
from struct import unpack, pack
|
||
|
|
|
||
|
|
|
||
|
|
def patch(bin_path):
|
||
|
|
with open(bin_path, 'r+b') as bin:
|
||
|
|
# Read entries 0 through 6 (Little Endian 32bits words)
|
||
|
|
vector = [unpack('<I', bin.read(4))[0] for _ in range(7)]
|
||
|
|
|
||
|
|
# location 7 (offset 0x1C in the vector table) should contain the 2's
|
||
|
|
# complement of the check-sum of table entries 0 through 6
|
||
|
|
bin.seek(0x1C)
|
||
|
|
bin.write(pack('<I', (~sum(vector) + 1) & 0xFFFFFFFF))
|
||
|
|
|
||
|
|
|
||
|
|
def is_patched(bin_path):
|
||
|
|
with open(bin_path, 'rb') as bin:
|
||
|
|
# The checksum of the first 8 table entries should be 0
|
||
|
|
return (sum([unpack('<I', bin.read(4))[0] for _ in range(8)]) & 0xFFFFFFFF) == 0
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
bin_path = "C:/Users/emimon01/releases/emilmont/build/test/LPC1768/ARM/MBED_A1/basic.bin"
|
||
|
|
patch(bin_path)
|
||
|
|
assert is_patched(bin_path), "The file is not patched"
|