CRF5 to BQL1 help - Samsung Galaxy S8 Questions and Answers

I am trying to downgrade my firmware from 8.0 oreo crf5 to 7.0 nougat bql1 and when i attempt to flash the firmware i get an error on odin and a fuse 5 binary 2 error on the phone, can some one help please?
I have a SM-G950U Snapdragon variant.

You are attempting to flash an old BOOTLOADER to your phone. That's what the error means.
Starting Android Oreo, Once you flash a new version of bootloader, you are only then allowed to flash same version or higher of it. Downgrading is not allowed.

Can you use N with the new BL?

Related

I have upgraded my phone(sm g935a)to Oreo i want to downgrade it

Kindly guide me someone i want to downgrade to marshmallow on SM G935A .. i have tried the apk1 rom but failed to flash please help...
You'll get used to Oreo, it's pretty good so far.
Assuming it's still on bootloader 4, you can downgrade to any firmware build using BL4. I don't recall off the top of my head if there was ever a MM build that used BL4, but that's the restriction. Anything else will either not flash or brick your device. You will need a modded version of ODIN to do the downgrade.
why do you want to downgrade?

S7EDGE - downgrade from oreo to nougat

Hi
It's possible to downgrade my s7edge from oreo to nougat?
Flashing BL from nougat doesn't work cuz says fail so...
Some ideas?
Because your firmwire its binary u3, and that is impossible to downgrade from oreo to nougat.
yungshadow said:
Hi
It's possible to downgrade my s7edge from oreo to nougat?
Flashing BL from nougat doesn't work cuz says fail so...
Some ideas?
Click to expand...
Click to collapse
https://forum.xda-developers.com/s7-edge/how-to/guide-how-to-downgrade-android-oreo-8-0-t3821495

update firmware but not bootloader?

I have a G930V running G930VVRU4BRC2. Is it possible to update to the latest firmware, G930VVRUACSF2, via Odin without updating the bootloader too? If not, do i have to stick with the latest in the v4 bootloader, G930VVRS4CRI1? Is there a reason I should not update my bootloader too? Like the ability to downgrade?
Thanks.
Trust me you don't want to update and to awnser your question I'm not sure but I am sure that the firmware itself has the bootloader number so by flashing from RS4 witch is bootloader 4 to RUA witch is bootloader 10 it would be impossible to downgrade just upgrade to a bootloader 7 and lower you should be fine

need help please rom flashing problems

hi hope i'm in the right place, my sm-g935f had an error with an ota update and got brick with the error binary locked with frp lock or something like that. i'm trying to downgrade from oreo to mashmellow and on odin it fails as soon as i start,same goes for when i tried nougat, can someone please help the only rom that flashes is oreo
official rom you can only install the latest version. Android 6 or 7 only to custom roms ported from other devices. Blocking the bootloader does not allow you to downgrade.
Nivi1993 said:
hi hope i'm in the right place, my sm-g935f had an error with an ota update and got brick with the error binary locked with frp lock or something like that. i'm trying to downgrade from oreo to mashmellow and on odin it fails as soon as i start,same goes for when i tried nougat, can someone please help the only rom that flashes is oreo
Click to expand...
Click to collapse
It's failing when you flash in Odin because you have a higher bootloader/binary. When you try flashing 6.0 or 7.0 software eventhough it's stock Samsung firmware, your Binary number is higher than the binary on the 6 or 7.0. This is from what I've seen been talked about here and elsewhere. Do you have to Downgrade?

is it possible to downgrade SM-G950F?

Hello,
Is there a way to dowgrade the bootloader of SM-G950F with stock fw G950FXXUCDUD1 to further flash a stock fw Android 8?
- flashing a downgraded bl with twrp?
- with "combination" fw?
- with a modified stock bl flashed with Odin?
...?
Thank you!
No. Samsung will not allow flashing of lower bootloader versions numbers.
Hello, thank you for your answer.
Even with a combination fw or directly flashing an older bootloader with twrp?
No.
Combination roms follow stock firmware regarding bootloader version ( can't downgrade). TWRP is a recovery image to replace stock, You can do more things in twrp over stock except downgrade stock firmware.
spawnlives said:
No.
Combination roms follow stock firmware regarding bootloader version ( can't downgrade). TWRP is a recovery image to replace stock, You can do more things in twrp over stock except downgrade stock firmware.
Click to expand...
Click to collapse
Ok, but what about this thread which seems to say it's doable with combination roms?
(Method) For everyone who wants to Downgrade Galaxy S8 to Oreo/Nougat
Hey guys! I recently read many Questions About downgrading the Galaxy S8 to 7.0/8.0 after we got the 5x Bootloader. Well many of you say NO but What many of you forgot is that there is a way to Downgrade your phone. I already had that Problem...
forum.xda-developers.com
I've seen many guides on how to downgrade stock firmware. Most of them revolve around editing stock firmware. None of them mention whether the bootloader version was actually downgraded. To me personally you are essentially trying to install a custom type rom using by using stock firmware.
spawnlives said:
I've seen many guides on how to downgrade stock firmware. Most of them revolve around editing stock firmware. None of them mention whether the bootloader version was actually downgraded. To me personally you are essentially trying to install a custom type rom using by using stock firmware.
Click to expand...
Click to collapse
I checked and you're right. The minimal configuration for flashing the bl is a tar with cm.bin and sboot.bin and this leads to the usual error "... check fail(cm) device : x binary : y" (whatever odin version used... patched or stock)
reverse engineering sboot and cm.bin and changing the binary release doesn't help because the code is signed and verified by the PBL from the ROM.
The only way to do it should be to connect to the exynos jtag / uart / ? and to reverse engineering the soc (!) modifying the way the PBL check the SBOOT.
Adam Outler a researcher did it on GalaxyS (1 or 2!) more than ten year ago... (https://forum.xda-developers.com/t/how-to-hack-hardware-binary-and-bend-it-to-your-will.1338073/)
So... I think is doable with a lot of talent and patience...
Anyway, thank you for your help!

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