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Flashed a T-mobile rom

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jmichaels1982
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Default Flashed a T-mobile rom

So using safe strap, I successfully flashed http://forum.xda-developers.com/show....php?t=2468083 From the T-mobile thread. The Phone fired up, the only thing I havent gotten to work yet is WIFI.

Now Kies is recognizing the phone as a T-mobile phone.

Does that mean i can use Kies to flash the T-mobile Bootloader on it, and make it a T-mobile phone with unlocked bootloader ?

Or will this result in a complete Hard brick ?
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bftb0
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Quote:
Originally Posted by jmichaels1982 View Post
So using safe strap, I successfully flashed http://forum.xda-developers.com/show....php?t=2468083 From the T-mobile thread. The Phone fired up, the only thing I havent gotten to work yet is WIFI.

Now Kies is recognizing the phone as a T-mobile phone.

Does that mean i can use Kies to flash the T-mobile Bootloader on it, and make it a T-mobile phone with unlocked bootloader ?

Or will this result in a complete Hard brick ?
Kies talks to the O/S (at first, at least), not the bootloader - so that is why it thinks the phone is a T-Mobile version. It probably does not even check the bootloader version.

Note that the way Safestrap works, flashing of a kernel appears to work, but only because Safestrap has replaced the /dev/block/mmc* filesystem entry that normally points to the (flash memory) boot partition with a symbolic link to the null device (/dev/null); so /system (the "ROM") gets flashed, but the the flashing of the kernel never actually happens - that data is literally thrown away (the Verizon kernel is left untouched). That's the way Safestrap is supposed to behave ... so that ROM devs don't need to prepare a normal ROM and also a "Safestrap Version". The kernels get thrown away when using Safestrap even though the recovery will shown them as having been flashed.

So, what you have now on your phone is T-Mobile /system + VZW kernel (boot). That's probably why WiFi isn't working (for instance if WiFi was implemented as a loadable kernel module in the T-Mobile case ... kernel modules can only rarely be interchanged between different kernels.)

I do not believe it is safe to believe that because Kies sees "T-Mobile" that you have found a gateway for converting a SM-N900V into a SM-N900T.

iirc, the partitioning layout is different between the VZW version and the Tmo version; since even a full Odin flash does not replace all the original partitions (efs and others), I'm pretty skeptical that what you suggest will work the way you want it to. I don't think Kies ever does re-partitioning (not to mention that neither Kies nor Odin can replace information that doesn't exist in the flash imaging files).


What you are suggesting is completely uncharted territory; if you take the plunge I think you should assume that it is at least as likely that you will have a hard brick as any other possible alternative... ... and that a hard-brick outcome is probably the most likely.


If you are feeling bold with your money, take all the usual precautions - in addition to backing up all your files do a

# dd if=/dev/block/mmcblk0 bs=8192 count=256000 of=/sdcard/200mb_mmcblk0_dump.bin

on the off chance that a "SD card unbricking" method would work. (afaik, that method has not been reported to work successfully on a SM-N900V to date).


.
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jmichaels1982
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(Last edited by jmichaels1982; 9th March 2014 at 10:29 PM.)
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Quote:
Originally Posted by bftb0 View Post
Kies talks to the O/S (at first, at least), not the bootloader - so that is why it thinks the phone is a T-Mobile version. It probably does not even check the bootloader version.

Note that the way Safestrap works, flashing of a kernel appears to work, but only because Safestrap has replaced the /dev/block/mmc* filesystem entry that normally points to the (flash memory) boot partition with a symbolic link to the null device (/dev/null); so /system (the "ROM") gets flashed, but the the flashing of the kernel never actually happens - that data is literally thrown away (the Verizon kernel is left untouched). That's the way Safestrap is supposed to behave ... so that ROM devs don't need to prepare a normal ROM and also a "Safestrap Version". The kernels get thrown away when using Safestrap even though the recovery will shown them as having been flashed.

So, what you have now on your phone is T-Mobile /system + VZW kernel (boot). That's probably why WiFi isn't working (for instance if WiFi was implemented as a loadable kernel module in the T-Mobile case ... kernel modules can only rarely be interchanged between different kernels.)

I do not believe it is safe to believe that because Kies sees "T-Mobile" that you have found a gateway for converting a SM-N900V into a SM-N900T.

iirc, the partitioning layout is different between the VZW version and the Tmo version; since even a full Odin flash does not replace all the original partitions (efs and others), I'm pretty skeptical that what you suggest will work the way you want it to. I don't think Kies ever does re-partitioning (not to mention that neither Kies nor Odin can replace information that doesn't exist in the flash imaging files).


What you are suggesting is completely uncharted territory; if you take the plunge I think you should assume that it is at least as likely that you will have a hard brick as any other possible alternative... ... and that a hard-brick outcome is probably the most likely.


If you are feeling bold with your money, take all the usual precautions - in addition to backing up all your files do a

# dd if=/dev/block/mmcblk0 bs=8192 count=256000 of=/sdcard/200mb_mmcblk0_dump.bin

on the off chance that a "SD card unbricking" method would work. (afaik, that method has not been reported to work successfully on a SM-N900V to date).


.
Thank you for your very thorough & patient explanation. I used to have a DEV ED. phone, and used Kies on it, that resulted in flashing retail edition bootloader on mine & locked the phone up. It no longer says Developer mode on the phone.

I finally got through to Samsung, and for now they have agreed to re-flash it with Developer Edition bootloader after a lot of talk.

But as it stands I have no warranty on the phone, so I cant attempt it.

The idea came to me when I used Kies and it converted my Dev Edition to Retain edition.

I did know that safe strap will not flash the kernel, but I also do know that T-mobile kernels are compatible with Verizons. So I was looking for T-mobile rom that has no Aroma in it, because I am thinking about joining t-mobile.

With a locked bootloader, i figured as long as the rom does not have Aroma in it, every thing should work and boot up, and i was right, except for the wifi thing.


Didnt know all the technical details though, so thank you for shedding light. I did lose my efs partition many times when my phone was DEV ED, but lucky I used TWRP to back up my efs, so I restored it, and it fired right up. It saved me from many bootloops, but your point did remind me, that odin does not restore efs, I think.

Not sure how kies is any different than odin.


Thanks again !

EDIT: NVM about wifi not working, I flashed http://forum.xda-developers.com/show....php?t=2588075 and now everything works, just waiting on my SIM to see if wifi calling and T-mobile data will work.
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bftb0
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@jmichaels1982

Hey I mis-spoke ... sort of ... about the partitioning difference between the T-mobile (SM-N900T) and the VZW variant (SM-N900V). I wasn't absolutely sure, and saw a thread where someone said "I thought they were the same", so I did a little checking around.

I went over into the T-Mobile forum and found a thread where someone was providing a big "SD card unbrick image" for that phone (SM-N900T). The front end of that thing contains the partition table for the SM-N900T, so I compared it to the partition table in my (VZW SM-N900V) phone (using "gdisk" on linux - it will report the partition table from the primary GPT even though the secondary GPT is missing. You only need about 33 512-byte blocks from the beginning of the device /dev/block/mmcblk0 to get this info.)

Turns out that all the low level stuff - partitions 1 through 22 - have the exact partitioning on the Tmobile phone as on the VZW phone. (But that is no guarantee of identical contents of course). But the last three partitions are different, starting with the /system partition. The /system partition is a different size (even though it starts at the same LBA/sector offset), and the /cache and /data partitions are not only different sizes but start at different LBA block offsets, as well.

Code:
$ diff vzwpart.txt tmopart.txt | more
1c1
< Disk vzw-GPT.img: 8192 sectors, 4.0 MiB
---
> Disk Tmo-GPT.img: 8192 sectors, 4.0 MiB

Number  Start (sector)    End (sector)  Size       Code  Name

32,34c32,34
<   23          376832         5931007   2.6 GiB     8300  system
<   24         5931008         8028159   1024.0 MiB  8300  cache
<   25         8028160        61071326   25.3 GiB    8300  userdata
---
>   23          376832         5414911   2.4 GiB     8300  system
>   24         5414912         6438911   500.0 MiB   8300  cache
>   25         6438912        61071326   26.1 GiB    8300  userdata

So, this is where it gets a little interesting. The stuff which is sized identically in the device parititioning is all the low-level stuff (apnhlos, modem, sbl1, dbi, ddr, aboot, rpm, tz, pad, param, efs, modemst1, modemst2, boot, recovery, fota, backup, fsg, fsc, ssd, persist, persdata).

If it were possible to do what you suggested - flash the low-level Tmobile bootloader without completely bricking the phone - then the phone would not boot to the OS correctly, but it might be able to take a re-partitioning operation in Odin and actually repartition the device with the T-mobile layout. I don't know if the Kies images are the same as the Odin images - it is possible that Kies never performs PIT re-partitioning.

Still, this is highly highly speculative. And again it is worth nothing that full Odin flashes don't provide data for any of the partitions highlighted in red above. So all sorts of stuff could go wrong.

I think you are to be congratulated if you are able to get Sammy to re-flash your DE phone. That's an achievement given Samsung's DE support policy, which appears to be "none whatsoever". And it is certainly likely to be much safer than what is discussed above.


Just out of curiousity, do you remember what it was that happened to you in the past that bolluxed up your EFS partition?


cheers
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LillieBennett
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(Last edited by LillieBennett; 14th March 2014 at 12:58 AM.)
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That was very interesting. I'm hoping the story will complete.

SM-N900V DE
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