Removing Low battery/Disable savestate in Snes9xTYL 0.4.2 PBP

[Rick81]

I thought I found the ultimate portable Snes emulator when I found Snes9xTYL 0.4.2

The emulator is really good but there is one thing that freaks me out.

When the battery is low (about 30-40 minutes left) the emulator stops save stats, with the consequence that if you do not find a power cord in this time (sleep mode is inactivated when running the emulator) you lose all your progress.

I have downloaded the sourcecode and modified it (i.e. removed the Low battery/disable savestate feature) och put several hours in trying to compile it put it the compiler stops at a lot of errors (most externals). I have fixed a lot of problems but there no end of the errors.

As an backup I am thinking of directly modify the hexcode, since it should be possible to find out where one variable called os9x_lowbat is located.

There is a string (found by using hexeditor on the EBOOT.PBP file) close to this variable:

if (os9x_lowbat) {
      if (!((s_TotalFrame>>7)&15)) pgPrintBG(0,33,0xffff,"Low Battery/Saving disactivated");
      else pgPrintBGRev(0,33,0xffff,"                               ");
   }

And the variable is set at:
os9x_lowbat=scePowerIsLowBattery();

What I want to to is setting
os9x_lowbat=0 instead of the function.


Is this possible? And if it is, how do I do it? Is there a way to go from EBOOT.BPB -> assembler and then assembler -> EBOOT.PBP?

[Rick81]

I managed to hack the EBOOT.PBP to remove the Low battery/ Disable save state feature and did it in the following way:
* Unpacked the EBOOT.PBP by using "PBP Unpacker"

* Disassembled the DATA.PSP using "PSPDASM V0.20 by BOOSTER"

* Located the os9x_lowbat and scePowerIsLowBattery() in the C-code

* PSPDASM showed scePowerIsLowBattery() in plain text in assembler code

* Changed assembler lines (i.e. always setting os9x_lowbat to 0)
sw     r2,$3b00(r3)                    ;00016F44[AC623B00,'.;b.']
to
sw     0,$3b00(r3)                        ;00000CC8[AC603B00,'.;@.']

at addresses:
00016F44
00017DD8

and

sw     r2,$3b00(r16)                      ;00000BA4[AE023B00,'.;..']
to
sw     0,$3b00(r16)                       ;00000CC8[AE003B00,'.;@.']

at addresses:
0001D9F4
001266DC
00000BA4

and

(this change was required since in on place the return value from scePowerIsLowBattery was check before storing it in os9x_lowbat, this code always makes the branch, i.e. checks if 0 == 0)
beq    r2,0,$00000bd8                     ;00000BA0[1040000D,'..@.']
to
beq    0,0,$00000bd8                     ;00000BA0[1000000D,'..@.']

* Since the problem was I couldn't use the PSP compiler, I modified the DATA.PSP with the changes shown above in hex format i.e. 1040000D -> 1000000D. Note that the hexformat is swapped so the change is 0D 00 40 10 -> 0D 00 00 10 at adress 00000BA0 + offset (0x60)

* Packed the DATA.PSP and the other files to EBOOT.PBP

* Copied the the PSP and it did work..

A bit weird that it is easier the hack the machine code then getting a script that should install everything in the PSP toolchain to work, but I solved the problem.

[AlphaDingDong]

Lol.  Toggling one bit solved your problem.

[Sakuryu]

Can you send me a copy of that im trying to mod it myself and things are not going well x.x