After MCU unlock, disassembly will get assembly language, not “C “or “Java”. If you can understand assembly language, you can certainly modify it.
What can modify the MCU crack program theoretically, but it is too difficult to do in practice. Because what unlocks is a machine code program, it needs to be disassembled and compiled into an assembly program, and then read these programs to modify. Suppose the original program is written in C language. In that case, the compiled machine code program is decrypted and then decompiled to get the assembly program is complicated to read, let alone modify. Suppose the original program is not long and written in assembly language. In that case, It can read the decompiled program after decryption, but it needs a solid ability to write an assembly language program. Therefore, in general, the IC unlock program is for machine code, not for modification, but for directly programming the machine code program of crack into its MCU. This requires the same hardware as the original circuit.