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I need to patch an arm7 program by replacing this fopen function by another function.
.text:00018D68 52 D7 FF EB BL fopen
...
.plt:0000EAB8 ; FILE *fopen(const char *filename, const char *modes)
Do you know how to calculate the 24 bits that I need to write after EB? The documentation is not very clear. I tried to find a Branch offset calculator but not found.
Thx,
you can use https://www.keystone-engine.org/showcase/ assembler
from keystone import *
target = 0xDEADBEEF
current = 0x18D68
ks = Ks(KS_ARCH_ARM, KS_MODE_ARM)
bytes(ks.asm("bl {}".format(hex(target)), current)[0]).hex()
