The Seven schrieb: > The first few bytes look like valid ARM reset vectors, I doubt that they > would be valid as THUMB. I also doubt that there is a way to make the > processor execute the RESET code at 0x00008000 as THUMB code. I'll > nevertheless try to disassemble it as THUMB today... > The Vectors get totally junky when trying to decode them as THUMB. The code at 0x00008000 looks alot better in THUMB than in ARM, but still looks garbled to me. Yes, there seem to be conditional branches to valid addresses (not too far away from the branch itself), but this is probably caused by the fact, that ARM justs supports much weirder instructions than THUMB, so the result of decoding random bytes as THUMB will look much better than the ARM one. Nevertheless, the code one gets from a THUMB disassembly there still doesn't make any sense at all. Looks like it's in fact crypted.
If the apple guys were clever, they would have used the internal ROM as some kind of micro bootloader for the 8Mb flash, and they would have provided some recovery option there, so that one can restore a misflashed bootloader flash from there, using code, that will NEVER get reflashed at all! I rather doubt that, (because using a processor that doesn't support code protection is just dumb from their point of view, so they can't have been too bright ;), and secondly, why should they provide a possibility to restore that? The'll rather want to sell a new iPod.) but it would really have been cool ;) > -----Original Message----- > From: Bahattin TOZYILMAZ <[EMAIL PROTECTED]> > Sent: Samstag, 17. Mai 2008 05:59 > To: Hardware and developpement mailing list. <[email protected]> > Subject: Re: [Linux4nano-dev] Readout in Binary > > I tried to investigate the THUMB code probability. What i could > understood is that, first 40 or so instructions (i dont have an ARM > emu, and i dont know how to use GBA emu's well) loads some registers, > and makes branchs. I dont think they used a second protection to > defend iPod, and our binary file should contain some machine > instructions. Can it be valuable to use an emu to investigate thumb > code? > _______________________________________________ Linux4nano-dev mailing list [email protected] https://mail.gna.org/listinfo/linux4nano-dev http://www.linux4nano.org
