Develop Bugs

M8 starting up in Fastboot, won't load installed ROM

I've stuffed something up along the way and now my M8 seems to refuse to load any ROM I've installed on it. What's the best way to go about fixing this? It's unlocked with S-Off.

Flashing an RUU is a silver bullet for starting over, as an RUU formats all your device's partitions and flashes them with stock images.
You'll need to provide CID & MID or your current firmware version (i.e. 4.16.401.10) if you need help locating a compatible RUU.
Cheers

Need some more details to see why the phone won't boot into OS after flashing a ROM.
Is an OS number indicated on the bootloader screen? If so, what is it?
What version TWRP?
What ROMs have you tried?

shirreer said:
Flashing an RUU is a silver bullet for starting over, as an RUU formats all your device's partitions and flashes them with stock images.
You'll need to provide CID & MID or your current firmware version (i.e. 4.16.401.10) if you need help locating a compatible RUU.
Cheers
Click to expand...
Click to collapse
I've tried flashing a few different RUUs and they all come out with an error 155. Googling it suggests I need to relock my bootloader but locking it and running the RUU again gives me the same error. I'm using SuperCID 11111111 and my MID is 0P6B70000. Currently on firmware 4.16.1540.8.
redpoint73 said:
Need some more details to see why the phone won't boot into OS after flashing a ROM.
Is an OS number indicated on the bootloader screen? If so, what is it?
What version TWRP?
What ROMs have you tried?
Click to expand...
Click to collapse
My OS number is 4.16.1540.8, I've tried TWRP 2.7.0.1, 2.8.7.0 and 3.0.0.0, roms I've tried include CM13, SkyDragon and a stock TWRP backup I found in another thread here.

roseyhead said:
I've tried flashing a few different RUUs and they all come out with an error 155. Googling it suggests I need to relock my bootloader but locking it and running the RUU again gives me the same error. I'm using SuperCID 11111111 and my MID is 0P6B70000. Currently on firmware 4.16.1540.8.
Click to expand...
Click to collapse
Your MID and firmware number don't jive; and it can indicate something pretty dangerous (and possibly a radio bricked phone).
Need more info on what you've done.
Do fastboot getvar all, and post the output (delete serial number and IMEI before posting).
Was the phone new and stock (unmodified) when you got it; or did it have a previous owner?
Please list all the mods you have applied (s-off, changed CID, changed MID? etc.).

Ok, here's what getvar all reports:
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.24.21331147A1.09G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 4.16.1540.8
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno: -snip-
(bootloader) imei: -snip-
(bootloader) imei2: Not Support
(bootloader) meid: 99000499014851
(bootloader) product: m8_whl
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B70000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: 3aa067db
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.035s
I bought the phone second-hand, it was running a custom ROM (SkyDragon) with cid already set to 11111111 and I wanted to return it to stock. I got the Unlocked/Developer RUU from HTC's site but that didn't start up for me so I tried a bunch of stuff, fiddling with firmwares and unlocking/relocking bootloader and so on but in the end the RUU just hadn't downloaded properly. Once I managed to get the RUUs to run they've all come up with error 155 when they start the flash and flashing the rom.zip direct gives me an error (I forget if it's the same or different)
I've also tried restoring assorted TWRP backups, installing new roms and so on, directly flashing boot.img, things seem to flash ok but the phone just boots direct into fastboot.

Update: I'm not sure what went differently this time but I've installed the latest Cyanogenmod nightly and it's starting up as expected.
I'd like to get back to stock though. What's the best way to go about doing this? The phone was already modified when I got it so I'm not sure what it would've had on it when it was purchased originally.
Edit: A bit of googling suggests this is a Sprint handset (I dismissed this to begin with since I'm in Australia and didn't think it'd be an overseas handset, but ok) so I've flashed 6.20.651.3 firmware and am waiting for a matching RUU to download. Fingers crossed!
Edit again: All sorted now, thanks for your help!

roseyhead said:
Update: I'm not sure what went differently this time but I've installed the latest Cyanogenmod nightly and it's starting up as expected.
I'd like to get back to stock though. What's the best way to go about doing this? The phone was already modified when I got it so I'm not sure what it would've had on it when it was purchased originally.
Edit: A bit of googling suggests this is a Sprint handset (I dismissed this to begin with since I'm in Australia and didn't think it'd be an overseas handset, but ok) so I've flashed 6.20.651.3 firmware and am waiting for a matching RUU to download. Fingers crossed!
Edit again: All sorted now, thanks for your help!
Click to expand...
Click to collapse
I'm glad you're all set. But for other users' benefit, here is a link to HTC's official Sprint RUU page, with instructions for flashing the RUU as well as a download link for Sprint M8 marshmallow RUU 6.20.651.3
Sprint RUU instructions page:
http://www.htc.com/us/support/htc-one-m8-sprint/news/
Sprint M8 marshmallow RUU 6.20.651.3 Direct Link:
http://dl3.htc.com/application/RUU_M8_WHL_M60_SENSE70_SPCS_MR_Sprint_WWE_6.20.651.3.exe
Cheers

i am having the same problem. i dont even know what carrier this phone was from. but the model number written on the back is OP6B110 M8x... and this is the result of getvar all..
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.08.20.0916
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 2.16.654.4
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) imei2: Not Support
(bootloader) meid: 99000499165808
(bootloader) product: m8_whl
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B70000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: 8a0f02ff
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0

roseyhead said:
I got the Unlocked/Developer RUU from HTC's site but that didn't start up for me so I tried a bunch of stuff, fiddling with firmwares and unlocking/relocking bootloader and so on but in the end the RUU just hadn't downloaded properly. Once I managed to get the RUUs to run they've all come up with error 155 when they start the flash and flashing the rom.zip direct gives me an error (I forget if it's the same or different)
Click to expand...
Click to collapse
Happy to see your sorted it out.
I agree it appears to be the Sprint version, based on the the MID (0P6B70000) and product name (m8_whl). While the MID can be modified, the product name is typically not (never seen a mod method for that - so the product name is very reliable).
That being said, I would strongly caution you moving forward, to not flash any firmware or RUU to this device except Sprint M8 firmware/RUU. Reason being, the partitioning on the Sprint phone is different from most other versions; and flashing another version's firmware can lead to a radio brick (phone boots, but nothing requiring the radio will work).
---------- Post added at 11:38 AM ---------- Previous post was at 11:30 AM ----------
mushfiq20 said:
i am having the same problem. i dont even know what carrier this phone was from. but the model number written on the back is OP6B110 M8x... and this is the result of getvar all..
(bootloader) version-main: 2.16.654.4
(bootloader) product: m8_whl
(bootloader) modelid: 0P6B70000
Click to expand...
Click to collapse
This is Sprint version, same as OP based on the model ID and product name. Although main version would indicate the Sprint Harmon Kardon version. RUU can be found at the bottom of the following webpage: http://www.htc.com/us/support/htc-one-m8-harman-kardon-edition-sprint/news/
The M8x designation on the back cover can't be trusted in this case. The back cover has been replaced to remove the "Sprint" logo branding. We've seen several phones like this (back cover replaced to remove evidence of branding) on the forum. You have to go by the getvar data.
Also, be sure to remove your IMEI and serial number from the getvar output. These are personal data, and should never be posted online.

redpoint73 said:
That being said, I would strongly caution you moving forward, to not flash any firmware or RUU to this device except Sprint M8 firmware/RUU. Reason being, the partitioning on the Sprint phone is different from most other versions; and flashing another version's firmware can lead to a radio brick (phone boots, but nothing requiring the radio will work).
Click to expand...
Click to collapse
Thanks a lot for the tip! I'll bear that in mind going forward.

Hi there I seem to be having similar issues. I purchased a refurbished M8. The case indicates 0P6B110 M8x however fastboot getvar all gives:
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.16.0.0000
(bootloader) version-baseband: 1.09.20.0209
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 3.30.651.2
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno: [REDACTED]
(bootloader) imei: [REDACTED]
(bootloader) imei2: Not Support
(bootloader) meid: 99000499237658
(bootloader) product: m8_whl
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B70000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: ab0efa49
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
Going off the info in the thread I downloaded RUU 6.20.651.3.
While verifying I want to update the ROM version it states:
From:
Image Version: 1.54.651.8
To:
Image Version: 6.20.651.3
After clicking next and progressing I get Error 155.
On the fastboot recovery screen shows:
*** LOCKED ***
m8_whl pvt ship s-off
cid-111111111
hboot-3.16.0.0000
radio-1.09.20.0209
opendsp-v38.2.2-00542-m8974.0311
os-3.30.651.2
eMMC-boot 2048
loading zip info fail
RUU
Any help with this would be greatly appreciated.

metalbassist33 said:
On the fastboot recovery screen shows:
*** LOCKED ***
m8_whl pvt ship s-off
cid-111111111
hboot-3.16.0.0000
radio-1.09.20.0209
opendsp-v38.2.2-00542-m8974.0311
os-3.30.651.2
eMMC-boot 2048
loading zip info fail
RUU
Any help with this would be greatly appreciated.
Click to expand...
Click to collapse
To run a Marshmallow RUU, you need to fastboot flash its firmware.zip first.
1. flash 6.20.651.3 firmware.zip
2. run RUU
You should be able to find the firmware.zip in Sprint section
Or you try to find one version lower (lollipop) than 6.20.651.3 RUU, run it then do OTA to 6.20.651.3

ckpv5 said:
To run a Marshmallow RUU, you need to fastboot flash its firmware.zip first.
1. flash 6.20.651.3 firmware.zip
2. run RUU
You should be able to find the firmware.zip in Sprint section
Or you try to find one version lower (lollipop) than 6.20.651.3 RUU, run it then do OTA to 6.20.651.3
Click to expand...
Click to collapse
Just to confirm, if I get a lollipop version, do I still need to fastboot flash a firmware.zip?

metalbassist33 said:
Just to confirm, if I get a lollipop version, do I still need to fastboot flash a firmware.zip?
Click to expand...
Click to collapse
No .. not needed, run Lollipop RUU then do OTA to Marshmallow

[q] cant update to mm

ok lets to the point, i cant update my m8 from RUU, zip or any method from this forum, this is my fastboot getvar all
version: 0.5
version-bootloader: 3.18.0.0000
version-baseband: 1.19.21331147A1.09G
version-cpld: None
version-microp: None
version-main: 2.22.707.4
version-misc: PVT SHIP S-OFF
serialno: 123456789223
imei: 352090060391351
imei2: Not Support
meid: 00000000000000
product: m8_ul
platform: hTCBmsm8974
modelid: 0P6B6****
cidnum: 11111111
battery-status: good
battery-voltage: 0mV
partition-layout: Generic
security: off
build-mode: SHIP
boot-mode: FASTBOOT
commitno-bootloader: 5e4b24e4
hbootpreupdate: 11
gencheckpt: 0
FYI : i have tested on RUU exe. it came with FAIL 155, RUU zip as well it cant be done, i have this problem almost one week, i have tried it from stock recovery and it keep fail, ota downloaded but cant install reason coz have a modified rom, so frustated for this phone

Have you tried flashing it via bootloader? Zipped ruu not exe. Renaming ruu.zip to 0P6BIMG (at least that's what is the name on sprint m8) and flashing it inside hboot itself?

JahatHNc said:
ok lets to the point, i cant update my m8 from RUU, zip or any method from this forum
FYI : i have tested on RUU exe. it came with FAIL 155, RUU zip as well it cant be done, i have this problem almost one week, i have tried it from stock recovery and it keep fail, ota downloaded but cant install reason coz have a modified rom, so frustated for this phone
Click to expand...
Click to collapse
flash the firmware first then flash RUU
Sent from my HTC One M8 using XDA Labs

@JahatHNc
What RUU version you have tried ?
Sent from my HTC One M8 using XDA Labs

ahmed.ismael said:
flash the firmware first then flash RUU
Click to expand...
Click to collapse
I think you are correct in your thinking, in that OP is trying to flash a Marshmallow RUU. In which case, they need to flash MM firmware, then they can RUU.

Problem going back to stock ROM after installing Google Play Edition with TWRP

Hello there.
I searched through several threads here (and other places) and I'm unable to solve the problem.
I have a HTC M8 European standard version (eg. Sense). I unlocked the bootloader using the official way and installed Marshmallow using OTA.
I was in the mood of trying Google Play Edition and reaching S-OFF (using Sunshine), rooting the terminal and with the help of TWRP, GPE was installed and it is working.
Now I want to go back to my senses keeping S-OFF and the terminal unlocked. And the problems began. Using any RUU, IMG or whatever I am unable to go back. A lot of links in some guides are broken and trying several RUUs in what seem to be the best places (below), I am unable to install it. With TWRP is the error 7 (that I am unable to solve) and with RUUs tells me the ROM is not the appropiate one:
The information about my terminal is as follows:
version: 0.5
version-bootloader: 3.19.0.0000
version-baseband: 1.29.214500021.12G
version-cpld: None
version-microp: None
version-main: 6.12.401.4
version-misc: PVT SHIP S-OFF
imei2: Not Support
meid: 00000000000000
product: m8_ul
platform: hTCBmsm8974
modelid: 0P6B10000
cidnum: HTC__304
battery-status: good
battery-voltage: 0mV
partition-layout: Generic
security: off
build-mode: SHIP
boot-mode: FASTBOOT
commitno-bootloader: 76df2b54
hbootpreupdate: 11
gencheckpt: 0
all: Done!
****************
M8_UL PVT SHIP S-OFF
CID-HTC__304
RADIO-1.29.214500021.12G
OpenDSP-v51.2.2-00593-M8974_FO.1015
OS-6.12.401.4
eMMC-boot 2048MB
Dec 17 2015,14:15:48.234
Somebody can help me, please?
Regards.
RUU Sources:
https://www.androidfilehost.com/?w=files&flid=13992
http://forum.gsmhosting.com/vbb/f48...-ruu-4-x-x-6-x-x-updated-19-3-2016-a-1940130/
http://androidruu.com/?developer=M8

Skip the relocking bootloader part ...
http://forum.xda-developers.com/showpost.php?p=64926626&postcount=6

ckpv5 said:
Skip the relocking bootloader part ...
http://forum.xda-developers.com/showpost.php?p=64926626&postcount=6
Click to expand...
Click to collapse
Thanks for answering.
If I understand you correctly I do not need to relock the telephone. Am I right?
Cheers.

aturdido said:
If I understand you correctly I do not need to relock the telephone. Am I right?
Click to expand...
Click to collapse
That is correct. With s-off, you never need to relock the bootloader in order to RUU. The bootloader lock check is bypassed with s-off.

Hello there.
Thanks for the help. I'm back to my senses.
Just two things related to the guide you suggest. As I had already installed HTC Sync I had both adb and fastboot so I used them.
Thanks again ckpv5 and redpoint73. :good:
Cheers.

Need help in getting back to stock

Hello,
I received an HTC M8 with a costume ROM.
I tried looking at the forum on how to get it back to stock but couldn't understand which RUU i need and where to get it.
In the System info it says crDroid version: crDroidAndroid-7.1.2-20170607-m8-v3.4.
Any help will be much appreciated.
Bootloader info:
*** UNLOCKED ***
M8_UL PVT SHIP S-ON
HBOOT-3.19.0.0000
RADIO-1.22.21331147A1.29G
OpenDSP-v46.2.2-00564-M8974_FO.0811
OS- (this is empty)
eMMC-boot 2048MB
Oct 30 2014,16:10:11.0
P.S
Can i turn the device into Google Play Edition
Shimshi

Post fastboot getvar all result (remove serial & imei no.) then we'll know what you need.
You can't turn it to GPE with S-On but you can install GPE rom after you update its firmware to Marshmallow.

ckpv5 said:
Post fastboot getvar all result (remove serial & imei no.) then we'll know what you need.
You can't turn it to GPE with S-On but you can install GPE rom after you update its firmware to Marshmallow.
Click to expand...
Click to collapse
Thank you for your reply.
As i understood i can turn my device to GPE after i get it back to stock and lock it back?
fastboot getvar all result:
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.22.21331147A1.29G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main:
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno:
(bootloader) imei:
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B11000
(bootloader) cidnum: HTC__044
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: a3d0cb0d
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.091s

Your device is same as mine which is a Asia WWE but yours in lower version.
You can get RUU_M8_UL_L50_SENSE60_MR_hTC_Asia_WWE_4.19.707.2_Radio_1.25.21331147A1.06G_20.69.4196.01_F_release_414204_signed.exe
from here - http://androidruu.com/?developer=M8
After you installed RUU, do OTA to 4.19.707.4 and finally to 6.14.707.1
You need to relock bootloader before you install RUU
After OTA is done up to 6.14.707.1, you can reunlock bootloader and install latest 3.1.x TWRP and install any custom ROM that you like or install GPE ROM.

ckpv5 said:
Your device is same as mine which is a Asia WWE but yours in lower version.
You can get RUU_M8_UL_L50_SENSE60_MR_hTC_Asia_WWE_4.19.707.2_Radio_1.25.21331147A1.06G_20.69.4196.01_F_release_414204_signed.exe
from here - http://androidruu.com/?developer=M8
After you installed RUU, do OTA to 4.19.707.4 and finally to 6.14.707.1
You need to relock bootloader before you install RUU
After OTA is done up to 6.14.707.1, you can reunlock bootloader and install latest 3.1.x TWRP and install any custom ROM that you like or install GPE ROM.
Click to expand...
Click to collapse
Hey ckpv5, thanks for your reply.
I couldn't relock the bootloader and couldn't understand how to use the RUU, from my knowledge it should be a zip file but it's an exe file.
Please advice?

Mostly the RUU that comes directly from HTC is in exe format as you can see here : http://www.htc.com/us/support/rom-downloads.html
What you need, read this : https://forum.xda-developers.com/showpost.php?p=64926362&postcount=4
I believe you already have adb/fastboot installed as you already gave me the getvar output. You need that HTC USB drivers and also a Windows PC with USB2.0
To relock bootloader
Boot your device to bootloader/fastboot and type this command after connecting to PC
fastboot oem lock
fastboot reboot-bootloader
To install RUU
After your device bootloader is relocked, while still in fastboot mode and connected to PC
Right click the exe and select run as Administrator, you'll see instruction screen. Follow all the steps as instructed .. accept, next, next, blablabla until it is completed.
Once finish, reboot your device.

Thank you ckpv5.
Sorry for the late response, it worked and now i'm back to stock.
Thank you very much.

stuck on HTC logo and the legal notice which rom will save me ? I can access twrp

Hi, I think screwed my htc m8 at&t .
I tried to do the RUU update downloaded from the htc webiste. [RUU_M8_UL_M60_SENSE70_ATT_MR_Cingular_US_6.20.502.5_combined]
I got an 132 error saying: "Signature error" and the update stopped . I clicked exit but the is stuck on HTC logo
so I unlocked the bootloader and flashed Twrp 3.2.1-0
now I can access the recovery and bootloader mode . what rom should I flash depending on the getvar bellow.
I'm confused .
here is the getvar info>
>fastboot getvar all
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: [email protected]
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 6.20.502.5
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: xxxxxxxxxxxxx
(bootloader) imei:xxxxxxxxxxxxxx
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul_ca
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B12000
(bootloader) cidnum: CWS__001
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: 205bdca3
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.035s
thanks a lot

Never mind turns out I had a faulty Download file. downloaded again with axel and I did reinstall without the error. HTC could really provide a hash for such a huge file.

bahha87 said:
I got an 132 error saying: "Signature error" and the update stopped . I clicked exit but the is stuck on HTC logo
so I unlocked the bootloader and flashed Twrp 3.2.1-0
Click to expand...
Click to collapse
Did you relock the bootloader before trying to RUU? Signature error is usually due to unlocked bootloader (when s-on, bootloader needs to be locked or relocked to install RUU).
But if you did relock the bootloader, and got an error, then it probably was just due to corrupted download as you stated.

redpoint73 said:
Did you relock the bootloader before trying to RUU? Signature error is usually due to unlocked bootloader (when s-on, bootloader needs to be locked or relocked to install RUU).
But if you did relock the bootloader, and got an error, then it probably was just due to corrupted download as you stated.
Click to expand...
Click to collapse
Yeah I did a relock. it was a corrupted RUU file. thanks for your suggestions.
I'm wondering if I can use other Roms like Android Revolution HD . with these specs : Android 6.0.0 (Marshmallow) - latest official HTC One 6.12.401.4_R (WWE) firmware (53.x series) considering the getvar info above.
+ can I use roms lower than this version version-main: 6.20.502.5 .
I'm a bit confused about downgrade without S-OFF, not sure if this depend on official android code names and versioning , or this version-main: 6.20.502.5.
in a nutshell should I consider Marshmallow 6.0.0 or version-main: 6.20.502.5 as a reference for what I can't or can flash with S-ON.

bahha87 said:
I'm wondering if I can use other Roms like Android Revolution HD . with these specs : Android 6.0.0 (Marshmallow) - latest official HTC One 6.12.401.4_R (WWE) firmware (53.x series) considering the getvar info above.
in a nutshell should I consider Marshmallow 6.0.0 or version-main: 6.20.502.5 as a reference for what I can't or can flash with S-ON
Click to expand...
Click to collapse
You can flash any Marshmallow, Nougat, Oreo ROMs intended for the "GSM" M8. So that is most M8 ROMs, but excludes ROMs specifically for the Verizon or Sprint M8, dual SIM, etc.
bahha87 said:
+ can I use roms lower than this version version-main: 6.20.502.5 .
I'm a bit confused about downgrade without S-OFF, not sure if this depend on official android code names and versioning , or this version-main: 6.20.502.5.
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What you describe (flashing a 6.12.401.4 based ROM in TWRP) isn't limited by s-on/off. You can flash a ROM in TWRP with little restriction.
When it's stated s-off is needed to "downgrade", this only applies to flashing an older version RUU or firmware.zip. In which case, yes s-off is required.
In fact, you can even flash a Lollipop ROM in TWRP and it will probably work fine. But Kitkat ROMs will have trouble (the Marshmallow firmware is not that far backward compatible). But I don't see many folks wanting a ROM as old as LP (3 years) at this point, anyway (much less Kitkat).

Thanks, that cleared everything. much appreciated