To quote, roughly translated: Today I'll write a tutorial to "fast-swap" between CFW 3.55 and OFW 3.70, using 2 HDDs... at the end of the tutorial, you'll be able to swap between the firmware just flashing a dump on your PS3 using Progskeet. (instead of downgrading and losing all data).
The first steps are not so easy, so take your time and go on, by the way, you must have some skill with Progskeet, and it must be 100% working on your console.
We need 2 HDD because the NOR flashes stores some parts of the current FW on the HDD so we will need 2 HDDs, one is for 3.55, and one is for 3.70.. We will call those HDD "A" (for 3.70) and "B" (for 3.55) don't mix them up!
Starting with a PS3 Slim with OFW 3.70.
1. Plug in HDD "B", format and prepare it if it's required by the PS3 and you should have your 3.70 up and running. 2. DUMP your actual NOR and call it "original dump 3.70.bin" 3. Now flash your "downgrade.bin" (edited with the personal data found in "original dump 3.70.bin") 4. Turn on your PS3 and be sure that the PS3 is asking you to press the PS button (downgrade.bin flashed correctly ) 5. Insert a 3.55 Downgrade dongle and enter factory/service mode. 6. Copy Lv2Diag.self by Jaicrab and the 3.55 NO CHECK UPDATE renamed as "PS3UPDAT.PUP" in the root of your USB Stick. 7. Plug in the USB Stick in the most-right USB port of your PS3 and wait for it to turn OFF. 8. Leave the factory mode using the other Lv2Diag.self 9. After the reboot, you need to configure and set up your system... now you have a fully working 3.55 CFW based on KMEAW "NO CHECK". 10. DUMP your actual NOR and call it "swap dump 3.55.bin" 11. Unplug HDD B and Plug in HDD A. 12. Turn on your PS3, plug in your USB Stick containing official 3.70 update and press start+select when asked. 13. When the PS3 reboots, check that the system is fully working and DUMP your actual NOR and call it "swap dump 3.70.bin".
NOW IT'S OVER! You should have "swap dump 3.55.bin" and "swap dump 3.70.bin" ... Now you just have to swap HDD and flash the corresponding dump:
HDD A = swap dump 3.70.bin
HDD B = swap dump 3.55.bin
WARNING: Do not install other CFW than the "NO CHECK" one... because it's used to make the "fast-swap" working... if you flash something different you will not be able to go between the 2 FWs. This CFW disable the Syscon checking at the startup... so it will not freeze or complain when the syscon says "3.70″ and your FW is 3.55
In case you wanna update your console with a future "3.80″ or-so firmware. Do not update your console when you are running 3.55 firmware! You have to go to "swap dump 3.70.bin" and then update as usual (XMB or recovery)... By the way, the downgrade is confirmed working only on 3.70... we haven't tested it on other FWs, you could lose the possibility to go back to 3.55!
Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
It is my understanding that you CAN downgrade on newer firmwares, but it requires this flasher.
Someone reported before that a v3.70 or 3.71 was downgraded using a hardware flasher. That's why you see these new v3.55 firmwares with the syscon patched, so they will run even if the ps3 had a newer firmware installed before.
I haven't looked into it since I'm already on v3.55, but that is what I thought when I read some of the previous news articles few weeks ago?
Following up on the QT Flasher for PS3 Test and Localized Versions for the ProgSkeet device, today PlayStation 3 developers uf6667, ago and bmx have made available the Winskeet40000 Rev 111002 software platform for Windows following by official Linux / Windows versions from http://twitter.com/#!/uf6667/status/121297431014027267.
New Qt GUI implemented
Linux and MacOS X support
Added predefined and user presets
Fixed ability to select invalid ranges
Added a file patcher
Flasher: Added support for canceling running operations
Flasher: Added USB device reset
Flasher: Added support for erasing as a stand-alone operation
Flasher: Added cycle period selection, should help with longer cables
Flasher: Added abort on error option
Flasher: Reodered operations, full read, full erase, full write
Flasher: Fixed bug with unreliable GPIO operation
NOR: Added new write mode "Dual word program"
NOR: Added display of total flash size
NOR: Fixed flashing of the second half of Samsung K8Q2815UQB and likely other dual chip NORs
NOR: Added erase block region configuration
NOR: Added selection of number of bytes for buffered write
NOR: Added support for Spansion S29GL128N90TFIR2
NAND: Made custom ranges work
NAND: Added Dual-NAND reading. Reads a block from two NANDs simultaneously, thereby doubling the speed.
If you're using 16MByte SAMSUNG NOR, please use Sector Size: 4kB/ Sector Count: 4096 and check "alternate writing method".
Differential flash, if you haven't noticed yet, will skip unnecessary writes (compares data on chip vs data in file)
Finally, below is GlitchSkeet Rev 111216 via http://www.tortuga-cove.com/forums/viewtopic.php?f=61&t=779#p2309 for those who wish to RGH with ProgSkeet (for XBox 360 users primarily at this time).
To quote: GlitchSkeet: is another bitstream written specifically for the ProgSkeet flasher, which will allow it to operate as a Glitcher like the many Glitch-Chips out there now that are used to perform the Reset Glitch Hack on the XBox 360 console.
The GlitchSkeet Bitstream currently have support for only the "Trinity/Slim" XBox 360 board model, It may need some more tweaking as well as adding support for other XBox 360 board models in later releases as time allows.
But anyway, all Skeeters/ProgSkeet owners have the right to test this Bitstream as it is in its current state.
Compatibility: This Bitstream is compatible with ProgSkeet v1.1 Crystal Blue only, ProgSkeet v1.0 Crystal White won't work.
Preparation: Short R12 and R9, Open R11 and R10
GP5 = I2C_SCL
GP6 = I2C_SDA
Adr0 = CPU_RST (you must add a Capacitor of 220pf/230pf/270pf between Adr0 & Ground)
Adr2 = POST_OUT1
Adr4 = DEBUG PIN / LED
N.B: the Injectus Jtag USB programmer is needed in order to update ProgSkeet with this Bitstream.
Credits to uf6667, Ago, bmx, nice69 and to all ProgSkeet Team members and testers.