diff options
Diffstat (limited to 'resources/utilities/ich9deblob/ich9deblob.c')
| -rw-r--r-- | resources/utilities/ich9deblob/ich9deblob.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/resources/utilities/ich9deblob/ich9deblob.c b/resources/utilities/ich9deblob/ich9deblob.c index a2819bf..5c49358 100644 --- a/resources/utilities/ich9deblob/ich9deblob.c +++ b/resources/utilities/ich9deblob/ich9deblob.c @@ -53,7 +53,7 @@ // The 2nd one is a "backup", but we don't know when it's used. perhaps it's used when the checksum on the first one does not match? // gbe checksum related functions -unsigned short GetChecksum(char* buffer, unsigned short desiredValue); // for GBe region (checksum calculation) +unsigned short GetChecksum(char* buffer, unsigned short desiredValue, char isBackup); // for GBe region (checksum calculation) unsigned short GetRegionWord(int i, char* buffer); // used for getting each word needed to calculate said checksum int main(int argc, char *argv[]) @@ -242,6 +242,8 @@ int main(int argc, char *argv[]) printf("\ndeblobbed descriptor successfully created: deblobbed_descriptor.bin \n"); + // ------------------------------------------------------------------------------------- + // calculate the 0x3F'th 16-bit uint to make the desired final checksum for GBe // observed values (from actual factory.rom dumps) 0xBABA 0x3ABA 0x34BA. spec defined as 0xBABA. // theoretically, this could be any l33t speak variation of BABA, eg 3434 or BA34, and so on, but this is untested. so far. @@ -249,24 +251,33 @@ int main(int argc, char *argv[]) // maybe only the 8 least significant bits are checked? or something deeper than that // it will need to be tested if those gbe regions that use something other than baba // will also work with the checksum changed to match baba (per datasheets) - unsigned short gbeCalculatedChecksum = GetChecksum(gbeBuffer, 0xBABA); + unsigned short gbeCalculatedChecksum = GetChecksum(gbeBuffer, 0xBABA, 0); // get the actual 0x3F'th 16-bit uint that was already in the supplied (pre-compiled) region data unsigned short gbeChecksum = GetRegionWord(0x3F, gbeBuffer); // from the original factory.rom - - printf("\ncalculated Gbe checksum: 0x%hx actual GBe checksum: 0x%hx\n", gbeCalculatedChecksum, gbeChecksum); + printf("\noriginal Gbe (main): calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeCalculatedChecksum, gbeChecksum); + + // same as above, but for 2nd region ("backup") in gbe + gbeCalculatedChecksum = GetChecksum(gbeBuffer, 0xBABA, 1); + // get the actual 0x3F'th 16-bit uint that was already in the supplied (pre-compiled) region data + gbeChecksum = GetRegionWord(0x3F+(0x1000>>1), gbeBuffer); + printf("original Gbe (backup) calculated Gbe checksum: 0x%hx and actual GBe checksum: 0x%hx\n", gbeCalculatedChecksum, gbeChecksum); return 0; } // checksum calculation for gbe region (algorithm based on datasheet) -unsigned short GetChecksum(char* regionData, unsigned short desiredValue) +unsigned short GetChecksum(char* regionData, unsigned short desiredValue, char isBackup) { unsigned short regionWord; unsigned short checksum = 0; + // if isBackup is true, use 2nd gbe region ("backup" region) + unsigned short offset = 0; + if (isBackup) offset = 0x1000>>1; // this function uses *word* not *byte* indexes. + int i; for (i = 0; i < 0x3F; i++) { - regionWord = GetRegionWord(i, regionData); + regionWord = GetRegionWord(i+offset, regionData); checksum += regionWord; } checksum = desiredValue - checksum; |