事先声明：我只负责翻译，用之前要有觉悟，变砖头别找我，也别找我当小白鼠，我一台是1.5一台是2.71，没必要降级也没法测试
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@是 Dark_AleX 公训模不是_玩笑的
n案大了c，要9.5MB，至@e I取降程式
有需要的人，LU自~
http://www.ps2nfo.com/modules.ph ... article&id=1253=================================================
To be used at your own risk. It is an UNTESTED software!
NOTE: This should NOT be used on TA-082 hardware!
This is an *experimental* downgrader for 2.50/2.60. Experimental means here that it has not been tested on a real device, although it has a theoretical base that it could work.
This software is free and untested, and i'm not responsable if it causes damages to your PSP. If you use this software, you agree that you are using this program at your own risk and that you won't blame the author for that.
"Someone told me that a downgrader for 2.50/2.60 was impossible. How does this work?"
This one uses another more risked technique (and i repeat: untested) than the MPH downgrader. It uses some sony libraries found in the 1.50 updater to perform the most critical steps, the logical format of the flash, and the ipl writing. See technical details for more info about how it works.
This software requires that someone with a 1.50 runs a little program and send you the output so you can init the downdate process. The 1.50 program is TOTALLY safe, it only dumps the flash of a 1.50 user and it also extracts some special prx's found in the 1.50 updater.
If you do not wish to have someone with a 1.50 do it for you, you can use the included MS_ROOT folder with the files in it instead. Inside is the "DOWNDATER" folder you can use with a 2.50/2.60 PSP to test the downgrade.
Instruction for the 1.50 user
-----------------------------
1) Copy the folders downhelper and downhelper% from the folder 1.50 HELPER folder to
/PSP/GAME/ in your memstick.
2) Obtain the 1.50 update EBOOT and put it in /PSP/GAME/UPDATE in your memstick.
3) Init the downhelper program.
It will dump your flash and some files from the updater eboot to the memstick.
4) After that, the program will exit. You can now delete the updater from /PSP/GAME/UPDATE
5) You'll notice that you have a new folder in the root of your memstick called "DOWNDATER". That's the folder you'll have to send to a 2.50/2.60 to let him test the downgrade.
Instructions for the 2.50/2.60 user
-----------------------------------
1) Copy the folder the DOWNGRADER/2.50/DOWNDATERTEST if you have 2.50
or DOWNGRADER/2.60/DOWNDATERTEST if you have 2.60 to /PSP/GAME/ in your memstick
2) Wait someone with 1.50 to pass you a folder called DOWNDATER and copy it to the root of your memstick.
3) Init GTA and the GTA Loader
4) In the GTA Loader menu, choose the downdater test. WARNING: the program won't output any display and any warnings, it will init the downgrader process inmediatelly.
5) You'll see the your memstick flashing. That means that your PSP is being flashed from the memstick.
You won't see any type of output in the screen (this is for safety). When the memstick finishes of flashing, WAIT at least a minute, and then reinit your PSP by holding the power button.
6) That's all. If all went right, you'll have 1.50. If it went less good, you'll still have 2.50/2.60. If all went wrong, you'll have a broken PSP (except in the case you have the mod-chip) Remember that you have accepted that risk.
Technical details
------------------
This program performs the following operations.
- It loads the ipl_update.prx and lflash_fatfmt.prx from the 1.50 updater.
- It performs a logical format of the flash0 partition using the function
sceLflashFatfmtStartFatfmt found in the lflash_fatfmt.prx
- It writes a dump of the 1.50 flash0 to the flash0.
- It writes the Initial Program Loader (Ipl) using the functions sceIplUpdateClearIpl
and sceIplUpdateSetIpl from the ipl_update.prx module. The ipl is embedded in that module.
Other considerations:
--------------------
- Users with TA-082 psp's shouldn't try this. Also, it may be better that at the beginning, only users with a 2.50/2.60 NOT from factory (they updated from a below firmware) try this.
-Dark_AleX