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[Q] (Simple) question about TWRP/2nd bootloader flashing

OP cecr

25th June 2014, 02:58 AM   |  #1  
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Having come close to hard bricking my device once already, I want to check some things before I attempt custom ROM installation.

I'm on 7.4.9, (rooted and with a factory cable to hand). The instructions for installing TWRP say to install "kfhd7-u-boot-prod-7.2.3" which I understand is the bootloader for OS 7.2.3 which is used because the later OS bootloaders were locked.

Now, if I flash that bootloader, and install TWRP, I can go on to flash a custom ROM. But if I just install TWRP for now, will the device still work with an 7.2.3 bootloader and the other images from 7.4.9 ? (or if I wish to continue with the stock ROM do I have to downgrade all images to 7.2.3?)

Also, are the checksums for the various stock images and files required to install TWRP around anywhere? Understandably, I'd like to verify them before starting.

thanks guys
25th June 2014, 06:54 AM   |  #2  
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Quote:
Originally Posted by cecr

Having come close to hard bricking my device once already, I want to check some things before I attempt custom ROM installation.

I'm on 7.4.9, (rooted and with a factory cable to hand). The instructions for installing TWRP say to install "kfhd7-u-boot-prod-7.2.3" which I understand is the bootloader for OS 7.2.3 which is used because the later OS bootloaders were locked.

Now, if I flash that bootloader, and install TWRP, I can go on to flash a custom ROM. But if I just install TWRP for now, will the device still work with an 7.2.3 bootloader and the other images from 7.4.9 ? (or if I wish to continue with the stock ROM do I have to downgrade all images to 7.2.3?)

Also, are the checksums for the various stock images and files required to install TWRP around anywhere? Understandably, I'd like to verify them before starting.

thanks guys

I would recommend you to keep a ROM and GApps zips on the sdcard,because we don't really know what evil Amazon has put into their latest update. So installing a second bootloader and TWRP might give you a bootloop. So keep a ROM so that you can flash it if you have a bootloop.
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25th June 2014, 05:47 PM   |  #3  
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thanks for your reply but I'm still in the dark.

what I really need to know is if I flash a bootloader from a different OS version, without TWRP etc, ie a straight swap of bootloaders, will the device still work normally? I don't want to try anything until I know I will be able to get out of trouble and have a functioning device.

I appreciate your advice to put a ROM and GApps on the sdcard, but what ROM? Stock? Do you mean the bin file or 3 images?

Or do you mean CM11 or similar?

Installing CM11 is my goal, but having run into trouble the first time after installing TWRP I want to reduce risks as much as possible. My intention is to install TWRP first, then make a backup of the stock ROM so I can go back to that if needbe, then to install CM11 and give that a go. The only thing stopping me is that the first time I tried, after installing TWRP I couldn't boot up the stock ROM, and I don't know why it happened.

Would I be better off downgrading to 7.4.6/7.4.8 before doing anything else? I assume I'll lose all my apps and settings if I do that?

In any case, I'd like to verify the checksums of any file I download to be on the safe side, but haven't seen a comprehensive list of files/images and checksums. Where can I get that info?
26th June 2014, 06:02 AM   |  #4  
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Quote:
Originally Posted by cecr

thanks for your reply but I'm still in the dark.

what I really need to know is if I flash a bootloader from a different OS version, without TWRP etc, ie a straight swap of bootloaders, will the device still work normally? I don't want to try anything until I know I will be able to get out of trouble and have a functioning device.

I appreciate your advice to put a ROM and GApps on the sdcard, but what ROM? Stock? Do you mean the bin file or 3 images?

Or do you mean CM11 or similar?

Installing CM11 is my goal, but having run into trouble the first time after installing TWRP I want to reduce risks as much as possible. My intention is to install TWRP first, then make a backup of the stock ROM so I can go back to that if needbe, then to install CM11 and give that a go. The only thing stopping me is that the first time I tried, after installing TWRP I couldn't boot up the stock ROM, and I don't know why it happened.

Would I be better off downgrading to 7.4.6/7.4.8 before doing anything else? I assume I'll lose all my apps and settings if I do that?

In any case, I'd like to verify the checksums of any file I download to be on the safe side, but haven't seen a comprehensive list of files/images and checksums. Where can I get that info?

I meant the zip files,not the images or binaries. And a custom ROM is recommended.
As for your concern,I suggest you to make image backups of the system,boot and recovery partitions,not a nandroid backup via TWRP.
If you install a 2nd bootloader+TWRP on 7.4.9,there's a high chance that it'll bootloop. So there's no point in making a nandroid of a system that bootloops. But by flashing the backup images that I told you to make,you'll go completely stock,no risk.

And if you want to automate the process,use FireFlash by stanga72 or my Flasher. There's a good chance of them working since they both worked on 7.4.6 and 7.4.8
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