Downgrade Bootloader check fail - Samsung Galaxy S9+ Questions & Answers

I have a S9+ G965F and I get the following error when trying to flash with Odin "sw rev check fail (bootloader) device: 9, binary: 2"
What is the problem? Would immensely appreciate help...

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You are flashing binary 2 firmware on device which has binary 9.
You need to flash binary 9 firmware like G965FXXS9DTD7
Flash this Firmware
https://androidfilehost.com/?fid=4349826312261807131

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Downgrade to android 8; not android 10
It sure worked, but... I am still on android 10... I was going to downgrade to android 8.
I got my firmware from SamMobile, but apparently it is binary 2? Where can I find the firmware for android 8? (Did not understand how to find android versions in androidfilehost)
Edit: I followed this tutorial on YouTube: "Downgrade Android 10 Roll Back To Android 9 On All Samsung Galaxy Phones S9+/S9/S10+/S10e/Note10" by Android Doctor

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In order to find your bootloader version you need to look at the 5th digit from the right, in the baseband in software version and you can easily find your android versions on sammobile, when you do get the current firmware you can also see listed the older firmwares

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-SaH- said:
It sure worked, but... I am still on android 10... I was going to downgrade to android 8.
I got my firmware from SamMobile, but apparently it is binary 2? Where can I find the firmware for android 8? (Did not understand how to find android versions in androidfilehost)
Edit: I followed this tutorial on YouTube: "Downgrade Android 10 Roll Back To Android 9 On All Samsung Galaxy Phones S9+/S9/S10+/S10e/Note10" by Android Doctor
Click to expand...
Click to collapse
you can not downgrade to oreo officially now. you can flash lite rom oreo a custom rom by lite team.

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Nisar Ahmed Nisar said:
you can not downgrade to oreo officially now. you can flash lite rom oreo a custom rom by lite team.
Click to expand...
Click to collapse
Why can't one downgrade when you have the firmware? (I am a total noob when it comes to this side of android)

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-SaH- said:
Why can't one downgrade when you have the firmware? (I am a total noob when it comes to this side of android)
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Click to collapse
I'm pretty sure Samsung prevents downgrading by blowing an e-fuse which prevents downgrading. I think they did this so that people cannot use special firmwares (without tripping knox) to remove FRP locks.

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Fortnite_Will_Die said:
I'm pretty sure Samsung prevents downgrading by blowing an e-fuse which prevents downgrading. I think they did this so that people cannot use special firmwares (without tripping knox) to remove FRP locks.
Click to expand...
Click to collapse
I don't know about s10 but we have been using combination rom to bypass frp for years

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How to downgrade from Android 10 to Android 9 on Galaxy S10e...
Fortnite_Will_Die said:
I'm pretty sure Samsung prevents downgrading by blowing an e-fuse which prevents downgrading. I think they did this so that people cannot use special firmwares (without tripping Knox) to remove FRP locks.
Click to expand...
Click to collapse
Has anyone figured out how to downgrade from 10 to 9 yet? I've tried a couple of tutorials, but they either not using and S10e but an older model WITHOUT Samsung bootloader locking, or they've been rooted - which I'd prefer to avoid.
I run into the error: "CHECK FAIL(BOOTLOADER) DEVICE: 7 BINARY: 3"
Then beneath this: "Pit_flash_binary - UNSUPPORTED VERSION".
Surely there MUST be a way to do this...?
i.

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Ivanlc73 said:
Has anyone figured out how to downgrade from 10 to 9 yet? I've tried a couple of tutorials, but they either not using and S10e but an older model WITHOUT Samsung bootloader locking, or they've been rooted - which I'd prefer to avoid.
I run into the error: "CHECK FAIL(BOOTLOADER) DEVICE: 7 BINARY: 3"
Then beneath this: "Pit_flash_binary - UNSUPPORTED VERSION".
Surely there MUST be a way to do this...?
i.
Click to expand...
Click to collapse
That means you are trying to flash older binary into your phone which is already in newer binary (bootloader). Meaning that no, you can't flash older firmware into a newer one.

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Fortnite_Will_Die said:
I'm pretty sure Samsung prevents downgrading by blowing an e-fuse which prevents downgrading. I think they did this so that people cannot use special firmwares (without tripping knox) to remove FRP locks.
Click to expand...
Click to collapse
ShaDisNX255 said:
That means you are trying to flash older binary into your phone which is already in newer binary (bootloader). Meaning that no, you can't flash older firmware into a newer one.
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Click to collapse
... Which means the e-fuse is something new since Android 8 or 9, as I've downgraded previously without this problem.
Would my only option now be to root, then or is there some way to downgrade the bootloader...?

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Ivanlc73 said:
... Which means the e-fuse is something new since Android 8 or 9, as I've downgraded previously without this problem.
Would my only option now be to root, then or is there some way to downgrade the bootloader...?
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Click to collapse
I mean you can technically downgrade as long as the bootloader versions are the same.
Just as an example, if you are on Pie U3 bootloader, you can downgrade to Oreo U3 bootloader as well. You wouldn't be able to downgrade if you were already on Pie U4 bootloader and wanted to downgrande to Oreo U3 bootloader.

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ShaDisNX255 said:
I mean you can technically downgrade as long as the bootloader versions are the same.
Just as an example, if you are on Pie U3 bootloader, you can downgrade to Oreo U3 bootloader as well. You wouldn't be able to downgrade if you were already on Pie U4 bootloader and wanted to downgrande to Oreo U3 bootloader.
Click to expand...
Click to collapse
Well, it's the bootloader for this accursed Android 10, so I assume this will make downgrading impossible, dammit. ?
Ok. Next Q; can I assume the only way I can downgrade the bootloader is by rooting the phone...?
(It's just rebooted by the way. I don't *think* Knox has been tripped, as the version info is all there and nothing indicating otherwise.)

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Ivanlc73 said:
Well, it's the bootloader for this accursed Android 10, so I assume this will make downgrading impossible, dammit.
Ok. Next Q; can I assume the only way I can downgrade the bootloader is by rooting the phone...?
(It's just rebooted by the way. I don't *think* Knox has been tripped, as the version info is all there and nothing indicating otherwise.)
Click to expand...
Click to collapse
I'm not sure if there's a way to do it with or without root to be honest, I've never had the need to research anything regarding downgrading the bootloader. Hope you find what you're looking for.

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ShaDisNX255 said:
I'm not sure if there's a way to do it with or without root to be honest, I've never had the need to research anything regarding downgrading the bootloader. Hope you find what you're looking for.
Click to expand...
Click to collapse
Only just seen this reply, my friend.
I've decided I'm gonna try the Magisk root method created by @topjohnwu and see how this works out.
I've now switched to using a Huawei P30 Pro (New Edition) as my main phone, so I can afford to risk rooting the S10e and seeing if I can downgrade it like this, as it seems a fairly safe way to go for a Root Noob.
I dunno if rooting will let me downgrade the bootloader; I'm just assuming it will, as I'll have root level access to the device.
... And If it all goes south, then not too much'll be lost, I hope - plus I'll have learned something new, I suppose...
i.