The console in question was a cech2504 with Datecode 1B. I guess that's where that will forward all Datecode and not downgrade for the moment
Lookin through the notice and the toil of extracting the rules and be 6 hours trying the downgrade in different ways
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You can use whatever you want, but here's my suggestion. If you already have Progskeet use that, if not you wait for the E3 to come out and see if it's any good. The Progskeet would most likely be cheaper but the E3 flasher will probably be easier to use.
... and If you're asking if your PS3 can be downgraded to 3.55 or less, it can.