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Changing bootloader: dead Defy

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By danimagrin, Senior Member on 7th June 2011, 04:28 PM
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Hey guys.

I executed dd if=/dev/zero of=/dev/block/mmcblk1p1

I've read in droid-developers.org that mbmloader is locked so I thought dd was going to give me write errors. I was wrong, and dd wrote zeros in the mbmloader partition. Now, phone is completely dead and I'll have to get a new one.

But I think that if it's possible to change mbmloader code with zeros, why can't we replace it with a new unsigned bootloader using dd? I couldn't find many real explanations why bootloader can't be replaced besides "it's locked and forget about it", so dd may be a way to replace it. We gonna need the opinion of someone with more knowledge about low-level programming and Defy's hardware.

Bye... And never type this in your Defy if you like it.
 
 
kaninabu
7th June 2011, 04:39 PM |#2  
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Quote:

I executed dd if=/dev/zero of=/dev/block/mmcblk1p1

Sorry, I simply cracked up at that line.

LOL
7th June 2011, 04:50 PM |#3  
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I have to try this trick:
https://www.droid-developers.org/wik...r_from_SD_card

Can someone please dump mmcblk1p1, it can be done with the reverse command:

dd if=/dev/block/mmcblk1p1 of=/mnt/sdcard/mbmloaderdump.img

Yaffs explorer can also dump it if you're afraid to run dd.

Thanks in advance!
7th June 2011, 04:53 PM |#4  
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If you managed to do
dd if=/dev/zero of=/dev/block/mmcblk1p1
shouldn't you also be able to
dd if=/dev/block/mmcblk1p1 of=~/bootloader.img ?
and if someone can do that and send you the image, shouldn't you also be able to repair your phone?

And why would you try anything like that anyway?? Especially without making a backup first?

I don't have my phone atm, i'm waiting for it to be returned from warranty. So i can't do any tests right now.

Edit: apparently you just found out yourself what I said
7th June 2011, 05:22 PM |#5  
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Thanks for your answer!

The problem is to recover the image if the phone doesn't even turn on.

As it's stated here, maybe there's a way to load it from SD Card:
https://www.droid-developers.org/wik...r_from_SD_card

But for trying that I'd need that someone posts a dump of mmcblk1p1
7th June 2011, 05:44 PM |#6  
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File uploaded.
Attached Files
File Type: zip mmcblk1p1.zip - [Click for QR Code] (32.3 KB, 105 views)
7th June 2011, 06:11 PM |#7  
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Thank you very much for the effort, but it didn't work.

Besides putting the file in root of sdcard, it seems that some code should be put on the phone to make it look on the sdcard for the mbmloader. Since the phone doesn't turn on, i can't put this code.
8th June 2011, 12:53 PM |#8  
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Quote:
Originally Posted by danimagrin

Thank you very much for the effort, but it didn't work.

Besides putting the file in root of sdcard, it seems that some code should be put on the phone to make it look on the sdcard for the mbmloader. Since the phone doesn't turn on, i can't put this code.

when you plug in the phone to a linux pc, do you see a USB device?
8th June 2011, 01:51 PM |#9  
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It seems that it's possible to replace the mbmloader with an unsigned bootloader. In fact, they've tried it on milestone, but failed.
(http://and-developers.com/custom_rec...native_methods)
Either you have to find a existent one or write a new one.
As to the former, we can't find an unsigned bootloader unless moto unlock it.
To do the latter one, you have to get all the information about the phone, another almost impossible thing.
here is the milestone boot chain, similer to defy.
http://and-developers.com/boot:boot_chain
8th June 2011, 09:38 PM |#10  
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Code:
# cat /proc/mtd
Code:
dev:    size   erasesize  name
mtd0: 00180000 00020000 "pds"
mtd1: 00060000 00020000 "cid"
mtd2: 000a0000 00020000 "logo"
mtd3: 00060000 00020000 "misc"
mtd4: 00380000 00020000 "boot"
mtd5: 00480000 00020000 "recovery"
mtd6: 008e0000 00020000 "cdrom"
mtd7: 0b260000 00020000 "system"
mtd8: 082a0000 00020000 "cache"
mtd9: 0ab20000 00020000 "userdata"
mtd10: 00200000 00020000 "kpanic"
Can't see mbm =)
Maybe you loaded mtd-hack?
9th June 2011, 03:05 PM |#11  
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Damn... Good guy with dead bootloader. I remember last time we could actually flash just the bootloader at will with phone Motorola E398 using ramloader or the famous flashbackup3.0. The E398 is really immortality. Hope this Defy can reach that height to justify its name.

Sent from my awesome Moto Defy Gingerbread 2.3.3 - XDA Premium
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