This is a recompiled M33 firmware that does not support backups. No ISOs, no CSOs, no nothing. If you want to run CFW but don't want the lure of piracy, you may consider giving this a try.

From XiaoFeiChong:

5.02 CFW OLD SCENER SCHOOL ONLY RELEASE!
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This release is ONLY for developers and TRULY OLD SCENERS SCHOOLS
NOT FOR ISO´S PLAYERS AND PIRACY USERS!

Update:
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- Put both files in the UPDATE folder and put the 5.02 EBOOT as 502.PBP in the same folder
- Launch app and follow instructions