Find out which Bootrom/Bootloader (Old/New) your iPhone 3GS has with f0recast

The new jailbreak tools for iOS 4 were available as soon as it was released. The sad thing is that these tools don’t work yet with iPhone 3GS with new bootrom. While checking the baseband of your iPhone is easy ( go to Settings > General > About ), to check the bootrom version you need to do a little work. But luckily, it’s very easy if you use f0recast.

f0recast was released by the developers behind sn0wbreeze. Forecast displays your iPhone’s serial number, baseband version, bootloader version information and model number. If you are on an iPhone OS 3.x device, it’ll tell you if you can unlock your iPhone or which tools can you use to jailbreak it. f0recast

All you need to do is download f0recast (works with both Mac and Windows), launch it and connect your iPhone 3GS and it’ll tell you all you need to know.

To find out if you have the new bootrom or the old one, read the line that says untethered. If it says Yes, then it’s the old bootrom and if it says No, you have the new bootrom in which case you can’t jailbreak iOS 4/ unlock it on your iPhone 3GS or iPod Touch 3G yet.

Download Links:

f0recast for Mac

f0recast for Windows


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  1. Hi, I read your elaborated post, but I still have some questions because different ways are leading to different answers

    version model modem firmware serial forcast tethered boot
    4.0(8A293) MC137LL 5.13.04 88926a7z3nr no 6.4
    4.0(8A293) MB717LL 5.13.04 5K00203Y3NR Maybe depens if refurb 6.4
    4.0(8A293) MB718LL 5.13.04 5K0221333NS Maybe depens if refurb 6.4
    4.0(8A293) MC137LL 5.13.04 88931MSB3NR no 6.4
    4.0.1(8A306) MB717LL 5.13.04 86924y663nr no 6.4

    As far as I know MC can't and MB can be Jailbreaked and Lower than 940 can and higher than that can't bejailbreaked.

    I have 2 MCs with smaller than 940 and I have 2 MBs with higher than 940 and one MB smaller than 940 but with an OS 4.0.1, which one of these are Jailbreakable and can you please illustrate why?

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