FreeCalypso > hg > fc-am-toolkit
changeset 28:58824cef4601
doc/C1xx-boot-utils: new article
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 12 Jun 2023 06:00:57 +0000 |
parents | 9e7ca43275eb |
children | 2168205c15be |
files | doc/C1xx-boot-utils |
diffstat | 1 files changed, 79 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/doc/C1xx-boot-utils Mon Jun 12 06:00:57 2023 +0000 @@ -0,0 +1,79 @@ +The present fc-am-toolkit package is mostly shell scripts, automating the +convoluted workflows for running FreeCalypso firmware on alien targets in +aftermarket configurations, but it also contains some C programs for working +with flash images read out of C1xx phones, particularly the bootloader part +which is absolutely critical on these brickable phones. The following 3 +utilities are provided - all 3 are used by c1xx-analyze-image script, but they +may also be useful on their own. + +c139-analyze-boot +================= + +This program takes a binary file containing either the complete flash dump from +a lower-submodel C1xx phone (C139/140 or C11x/12x) or the beginning of one (must +be at least 0x2064 bytes) and checks it for presence of lower-submodel-C1xx +bootloader code that must be present in the boot sector on these phones. The +program prints a single keyword on stdout, indicating its findings, and exits +successfully. The following 4 classifications are emitted by this program: + +fc + + compal-flash-boot-for-fc.bin bootloader has been identified, the patched + bootloader version we put in sector 0 on these Compal phones when we run + FC firmware on these phones. + +unlocked + + Found one of the lock-free bootloader versions (either C11x or C139), + or found a lockable bootloader version, but the lock word at 0x2060 is + set to 0xDDDDDDDD, meaning unlocked. + +locked + + Found one of the lockable, but otherwise good bootloader versions + (either C11x or C139), and the lock word at 0x2060 contains 0 or some + other value than the needed magic. This status indicates that the flash + image in its given state is boot-locked (bad), but it can be transformed + into a boot-unlocked image with c139-patch-dmagic - see below. + +unknown + + None of the known-good bootloader versions have been identified. The + bootloader you got may be one of the later versions that have been + locked down more heavily, and these flash images are EXTREMELY UNSAFE. + You should NEVER flash any such images back into a phone: our defenses + against bricking don't work with such maliciously modified bootloader + versions, and if you try to flash one (even if you are only seeking to + restore what you originally read out of the flash) and the process gets + interrupted in any way (meaning the full, long process), your phone may + be bricked beyond all recovery! + + If you are able to somehow break into a phone with one of these ultra- + malicious bootloader versions (and you must have been able to break in + somehow, if you got a flash image you are analyzing), the generally + recommended course of action is to make a one-way transition to a + better, non-malicious official Motorola firmware version. + +c139-patch-dmagic +================= + +This program needs to be run if c139-analyze-boot returned "locked" on your +flash image. This program opens the given binary file in writable mode and +patches the unlocking magic word 0xDDDDDDDD at offset 0x2060, thereby turning +the locked flash image into an unlocked one. If the image you've read out of +flash is a locked one, as determined by c139-analyze-boot, and you wish to +reflash that same fw version back into your phone (or into a different phone), +you MUST unlock the image with c139-patch-dmagic before flashing it with +fc-loadtool - if you proceed with flashing a locked image, you will have a very +high chance of bricking your phone (beyond all recovery!), as our regular +defenses against bricking don't work with locked bootloaders. + +c155-analyze-boot +================= + +This program is a very simplified logical equivalent of c139-analyze-image for +C155/156 subfamily. Perhaps it is because these phones are less common, but I +(Mother Mychaela) have not yet encountered any locked or otherwise modified +versions of C155/156 bootloader beyond the one known classic version. +c155-analyze-boot currently checks for this one known bootloader version, and +prints "ok" if the image matches or "unknown" otherwise.