Question about bootroms

**itzbilly** · 06-25-2010, 11:56 PM

Hi guys, I have a 3GS that was replaced by Apple.

The thing is, what I've found, after doing some extensive research is that the model and the serial number are vital to knowing whether you have an old bootrom, or a new bootrom.

I've found that if your model starts with MB, it is the older bootrom. It is also the older bootrom if your iPhone was sold before the 40th week.

I'm a bit confused about this because I have a MB model, 09 is the 4th and 5th digits of my serial number.

Normally, this SHOULD mean, is that I have an old bootrom 3GS, if I'm not mistaken.

The issue here, however, is that my 3GS was a replacement phone. The serial number ends in FW3NP, which I have never seen before (first time ever replacing any of my past iPhones). I also had issues with using sn0wbreeze 1.5.1, which supposedly worked with old bootroms but not with new bootroms, and was unable to jailbreak with it.

Can anyone tell me if the same rules apply? I was looking forward to using OS4. Please reply soon, thanks in advance.

**dhamien** · 06-26-2010, 08:11 AM

The MB/MC thing is a widespread misunderstanding. Model MC/MB can't be used to determine anything useful about the 3GS. Serial number isn't a very precise way to tell either, though it can be useful in a lot of cases where the phone was produced several weeks from the bootrom change window.

As your phone has 09 as 4th and 5th number, it's should be a new bootrom phone. It was produced in week 9 in 2010, meaning several months after the old bootrom phones were stopped being produced. However, as it's a refurb, you can't judge by the serial number. You'll need to put the phone in DFU mode and then use USBView to manually find the bootrom version. You can search for guides on how to do that.

Old bootrom is 'iBoot 359.3' and new is 'iBoot 359.3.2'

**itzbilly** · 06-26-2010, 08:34 AM

When following this guide: How to Check iPhone 3GS New Bootrom / Old Bootrom (iBoot) Version | Redmond Pie

I get iBoot 359.3. When using f0recast, it shows "Maybe-depends on if refurbished" for Tether.

Does that mean I still have the new bootrom? Or is the iBoot 359.3 the most important thing?

**Simon** · 06-26-2010, 08:57 AM

You have old bootrom if it shows 359.3 if following that guide

**dhamien** · 06-26-2010, 09:40 AM

Originally Posted by itzbilly

When following this guide: How to Check iPhone 3GS New Bootrom / Old Bootrom (iBoot) Version | Redmond Pie

I get iBoot 359.3. When using f0recast, it shows "Maybe-depends on if refurbished" for Tether.

Does that mean I still have the new bootrom? Or is the iBoot 359.3 the most important thing?

You have the old bootrom. f0recast isn't really a good tool because it relies solely on the serial number and then make a 'guesstimate' based on that. The only way tell for sure is by looking at the numbers, like you did, and see what version it is.

**itzbilly** · 06-26-2010, 12:08 PM

I see, that's great news. Another thing... I checked the guide that was posted on the front page for updating to iOS4... it says if I'm on 3.1.3 and jailbroken with spirit, I can't update. But I've also seen a guide either here or on redmondpie that says I restore to stock 3.1.3 and then update to 4.0.

Does anyone know if thats possible?

**Simon** · 06-26-2010, 12:42 PM

I believe you can go back to 3.1.2 and jailbreak with blackra1n or redsnow then you would be able to load a custom 4.0 ipsw. You would have needed your SHSH backed up to go back to 3.1.2 though. I know blackrain won't work on 3.1.3, not sure if redsnow was ever updated to work with old bootrom 3GS on 3.1.3 but I don't think it was.

**DJM AutoWerkz** · 06-26-2010, 12:46 PM

Redsnow works on 3GS u just have to choose 3.1.2 instead of 3.1.3 and works only on old bootrom I don't suggest new bootrom

**itzbilly** · 06-26-2010, 12:48 PM

Interesting.. have any of you tried 4.0 yet? My boss is on 4.0 on her 3G and tells me that it is much faster than 3.1.2..

**Simon** · 06-26-2010, 01:52 PM

Heven't tried stock 4.0 yet, just jailbroken with wallpaper and multitasking enabled. Like this it is a lot slower than 3.1.3.

**dhamien** · 06-26-2010, 04:17 PM

Originally Posted by DJM AutoWerkz

Redsnow works on 3GS u just have to choose 3.1.2 instead of 3.1.3 and works only on old bootrom I don't suggest new bootrom

This is incorrect. Only Spirit works on a 3GS on 3.1.3

@itzbilly
The only chance you have is if you can downgrade to 3.1.2 and jailbreak with blackra1n or redsn0w and then go from there to 4.0 with custom firmware.

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Hi guys, I have a 3GS that was replaced by Apple. The thing is, what I've found, after doing some extensive research is that the model and the serial number

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