I've been experimenting with BRAM now (free time, finally!). I confess, I like to play with the Myth, and I really would like to see this last feature working. Where are all the Myth MD users? Maybe they are happily enjoying their Everdrives and though I already have one, I suppose I'm one of the few who still plays the Myth occasionally. Contrary to what I've said before, I don't believe my device is defective, I believe very few users tried these features and didn't report issues.
If I turn off my console QUICKLY after copying a file from the internal RAM at the SCD Memory Manager, it will keep a non-corrupted BRAM content in the Myth SRAM. It is a matter of time, really. If I wait some seconds, exit SCD Memory Manager and enter again, that will be the time it takes to corrupt the data, presenting garbled names and absurd block sizes, preventing further writings (not enough space), except formatting.
So I decided to compare the BRAM dump files before and after glitching out. And I found out the altered data are just some bytes at the end of the file (maybe it's a "header" for game save index, name and size). Chilly Willy, if you're still lurking and is willing to take a look at this (because maybe you are the only one who could), I am posting a comparison of the two files, the good and the bad ones. Please don't feel pressured.
Anyway, I'll post some info.
The scenario is the same as before:
1) Created Sonic CD file in the internal memory by starting a Sonic CD game without the Myth in the MD.
2) Now using the NEO3-SD and the Myth menu, selected SCD_RAM.bin (made of "FF 03"'s) with "A", set it to SRAM slot 3 (the last 512Kb/64KB of 2Mb/32MB).
3) Disabled SRAM Manager to prevent any bad SD Card writes and restoring (possibly caused by connection/power issues). Battery is new and working.
4) Cleaned slot 3 in SRAM Manager.
5) Booted Sega CD with SCD_RAM.bin using "A" and "C" in the Menu DX.
6) In Sega CD Memory Manager, the External RAM was formatted, resulting in 1021 blocks free.
7) Sonic CD data (11 blocks) is copied to External RAM (Myth). Entering in "erase data" in SCD RAM Manager, it shows 1010 free blocks. Shut down the Mega Drive and I extracted the first Myth SRAM dump (the GOOD one, tested in Kega).
Then I proceeded returning to the Sega CD Memory Manager, and accessing the erase data screen, this time showing the corrupted data.
9) Extracted a second SRAM dump, this time with the BAD one so I could compare the files.
HexComp displayed the following changes:
File 1: C:\EMU\Fusion364\BRM\SCD_RAM_GOOD.CRM (65536 bytes, Start offset 0x0)
File 2: C:\EMU\Fusion364\BRM\SCD_RAM_BAD.CRM (65536 bytes, Start offset 0x0, Shift 0x0)
0000FF80: 00 20
0000FF81: D4 54
0000FF83: 00 20
0000FF84: 00 20
0000FF88: 03 20
0000FF89: 03 20
0000FF8A: 03 20
0000FF8B: 00 20
0000FF8C: 03 20
0000FF90: 00 20
0000FF91: 03 20
0000FF92: 00 20
0000FF93: 00 20
0000FF94: 00 20
0000FF99: D2 52
0000FF9A: F5 75
0000FFA1: 14 20
0000FFA2: F5 75
0000FFA8: 00 20
0000FFA9: 03 20
0000FFAA: 12 20
0000FFAB: 00 20
0000FFAC: 0A 20
0000FFB0: F5 75
0000FFB2: ED 6D
0000FFB9: A5 25
0000FFBA: 88 20
0000FFBB: 14 20
0000FFCB: 00 20
0000FFCC: 00 20
30 bytes changed, 11 locations
The game data itself is in the beginning of the files and is identical, so I conclude game data is intact, while the bad data is something related to the last bytes of the file before "SEGA_CD_ROM" and "RAM_CARTRIDGE". I looked for info about BRAM file structure but there's very few information on these ending bytes.
The good news (?) is that it glitches the same bytes and values every time I try these steps. Well, there is something going on here...
Well, now I'm going to get a life! Thanks for reading!
