[Q] Galaxy S2 won't reboot after root - Galaxy S II Q&A, Help & Troubleshooting

My galaxy s2 (GT-I9100 white) won't reboot after I root it and it stuck on the Startup screen and there's a yellow exclamation mark. It still can go into download mode again but I got no idea what to do in order to recover the phone... Anyone can help about it??? Did my phone just turn into a brick????:crying::crying::crying:
P/S: I am a Malaysian and this phone was bought in Switzerland and I never root it before.

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kaiwen10 said:
My galaxy s2 (GT-I9100 white) won't reboot after I root it and it stuck on the Startup screen and there's a yellow exclamation mark. It still can go into download mode again but I got no idea what to do in order to recover the phone... Anyone can help about it??? Did my phone just turn into a brick????:crying::crying::crying:
P/S: I am a Malaysian and this phone was bought in Switzerland and I never root it before.
Click to expand...
Click to collapse
Basics.... Reflash any custom rom with Odin. That will help.
Sent from my GT-I9100 using xda premium

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okti said:
Basics.... Reflash any custom rom with Odin. That will help.
Sent from my GT-I9100 using xda premium
Click to expand...
Click to collapse
Actually my friend sent me this kernel>>>CF-Root-SGS2_XX_OXA_LP1-v5.2-CWM5.tar
He told me to flash the kernel then only install custom...so I can directly flash the rom to my s2
by using odin???

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kaiwen10 said:
Actually my friend sent me this kernel>>>CF-Root-SGS2_XX_OXA_LP1-v5.2-CWM5.tar
He told me to flash the kernel then only install custom...so I can directly flash the rom to my s2
by using odin???
Click to expand...
Click to collapse
Yes, download and flash new rom, Then you have guarantee your phone will boot up because after flashing kernel you might get bootloop too.
Sent from my GT-I9100 using xda premium

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kaiwen10 said:
My galaxy s2 (GT-I9100 white) won't reboot after I root it and it stuck on the Startup screen and there's a yellow exclamation mark. It still can go into download mode again but I got no idea what to do in order to recover the phone... Anyone can help about it??? Did my phone just turn into a brick????:crying::crying::crying:
P/S: I am a Malaysian and this phone was bought in Switzerland and I never root it before.
Click to expand...
Click to collapse
This is because you flashed a wrong kernel for your phone.
# Quick question:
Is your phone on Gingerbread, Android 2.3.x or ICS (Ice Cream Sandwich), Android 4.0.x?
# If your phone is on ICS, then download and flash this kernel via Odin: www.gokhanmoral.com/public/files/siyahkernel/v3.0/Siyah-v3.5.2.tar
# If your phone is on Gingerbread, then download and flash this kernel via Odin: gokhanmoral.desean.net/siyahkernel/v2.6/Siyah-v2.6.14.tar
Sent from my GT-I9100 using Tapatalk 2

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Jokesy said:
This is because you flashed a wrong kernel for your phone.
# Quick question:
Is your phone on Gingerbread, Android 2.3.x or ICS (Ice Cream Sandwich), Android 4.0.x?
# If your phone is on ICS, then download and flash this kernel via Odin: www.gokhanmoral.com/public/files/siyahkernel/v3.0/Siyah-v3.5.2.tar
# If your phone is on Gingerbread, then download and flash this kernel via Odin: gokhanmoral.desean.net/siyahkernel/v2.6/Siyah-v2.6.14.tar
Sent from my GT-I9100 using Tapatalk 2
Click to expand...
Click to collapse
Thanks for that.
I have the I9100BVLPH stock ROM from T-Mobile UK on my phone so I downloaded the correct Chain Fire kernel (CF-Root-SGS2_XX_OXA_LPH-v5.2-CWM5.tar) from http://forum.xda-developers.com/showthread.php?t=1103399 and this caused the phone not to boot.
Thanks for the link to Siyah, I used the v4.1.5 kernel and it worked great.

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Hello there.
I'm in a bit of a trouble so I need some help. I've bought an S2 for my wife from a guy (in Ireland).
The phone was locked on Vodafone so I tried to root it maybe I'll be lucky to unlock it with out paying nothing. So, the phone is on Gingerbread with a BUKJ3 kernel. I've downloaded last night a CF root but by mistake I took a KG3 instead of KJ3. After flashing with Odin 1.85 I got stuck on the boot screen with the yellow triangle.
This morning I've downloaded another kernel as in KJ3 flashed with Odin, the phone is starting but no network coverage, I tried with different Sim cards but nothing so I went in recovery mode and wipe/format data, system, dalvik and cache as factory reset as well. Since that moment the phone won't boot, it gets stuck on the boot screen and yellow triangle.
I can go in recovery mode and download mode with no problem but I can't make it start.
I reflashed the kernel, I don't know what to do and tomorrow is my wife's birthday and I was trying to surprise her with a nice phone but instead looks like she is gonna get a brick ( I hope not)
Thank you guys for any help.

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Go to sammobile and get something like unbranded XWLP7 stock rom....flash via odin
Then use rachmats ics rooting guide
Backup efs folder and make nand backup
Then get unlock app(by helroz or chainfire)
Sent from my GT-I9100 using xda premium

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theunderling said:
Go to sammobile and get something like unbranded XWLP7 stock rom....flash via odin
Then use rachmats ics rooting guide
Backup efs folder and make nand backup
Then get unlock app(by helroz or chainfire)
Sent from my GT-I9100 using xda premium
Click to expand...
Click to collapse
Thank you for the reply. I don't mean any disrespect but for the last 3 hours I'm looking over kernels and forum and my brain is really wired now maybe.
I've had a look at sammobile but I can't find what you've recommended. A more specific link will be more than helpful.
Thank you very much anyway. If I'm getting advises it means I didn't bricked the phone so I might be able to fix it.
Once again thank you.

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You just go to sammobile,then register,then firmware and files,then put the info in the 4 fields
eg
Smartphone
Android
Gt-i9100
Then uk/ire XEU (or vodafone or whatever..but unbranded better)
Then youll see a list about firmware version and their release date
Eg
Lpt 4.0.4 ics jul 2012
Lp7 4.0.3 ics apr 2012
So download lp7 4.0.3 and flash with odin.
Then use the rooting guide in my sig
Then do the other things I said.

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theunderling said:
You just go to sammobile,then register,then firmware and files,then put the info in the 4 fields
eg
Smartphone
Android
Gt-i9100
Then uk/ire XEU (or vodafone or whatever..but unbranded better)
Then youll see a list about firmware version and their release date
Eg
Lpt 4.0.4 ics jul 2012
Lp7 4.0.3 ics apr 2012
So download lp7 4.0.3 and flash with odin.
Then use the rooting guide in my sig
Then do the other things I said.
Click to expand...
Click to collapse
Thank you very much. In the mean while I've managed to find exactly what you've said in your answer. I've choose the gingerbread version of the ROM cause that was what the phone had when I've bought it.
SO, now is it safe to go on ICS like I did half an hour ago with that Gingerbread rom?
Thank you and sorry about the noob question, never used an Samsung, only HTC.

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Yeah just do what I said.......not what you think!.

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theunderling said:
Yeah just do what I said.......not what you think!.
Click to expand...
Click to collapse
Did it, thank you very much. The phone start but somehow I've lost my IMEI number and base band. I must be really unlucky.
I've read that Odia can help in this matter but if anybody has any idea, I'll be happy to make a donation for getting back the IMEI number.
Once again thank you very much.

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theunderling said:
Yeah just do what I said.......not what you think!.
Click to expand...
Click to collapse
It's always about read read more.... And don't flash anything unless you are 100% sure...
Sent from my GT-I9100 using xda premium

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People contact Odia when theres a problem with their efs folder/no backup.
But you should have a backup and a nand backup.
I had the same problem yesterday and I restored efs folder/restored nand backup.....which got it back.
So try that or theres a thread about "restore imei in 9 easy steps".

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theunderling said:
People contact Odia when theres a problem with their efs folder/no backup.
But you should have a backup and a nand backup.
I had the same problem yesterday and I restored efs folder/restored nand backup.....which got it back.
So try that or theres a thread about "restore imei in 9 easy steps".
Click to expand...
Click to collapse
I know I was stupid enough not to read before flashing, but now it too late to think about that.
the thing is I've never used a galaxy phone until these days and I wasn't aware of all this things and I don't know how to restore this NAND backup IF I have one, as I didn't make any backup before flushing. I hope I'll get some help from somebody and as I've said, a nice donation will be on the way to the helper.

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Try GSII repair app.But you have to be rooted.