[HOW-TO] Downgrade HBOOT

[Guest behnaam]

THE ORIGINAL THREAD CAN BE FOUND HERE

After alot of playing around at the #modaco IRC and reading this thread I tried to actually downgrade my hboot from 0.75 to 0.66 (dont ask me how I got 0.66).

OBS! There is no reason to downgrade in case you already have hboot version 0.75 or a rooted 0.80 device. This guide is for future leaks of a ENG spl or such.

Now here are the steps I took:

1. Download a RUU with your desired HBOOT version. Note down the version of the RUU's ROM, e.g. 1.15.405.4.

You can find a list of RUU's here

2. Go to this mtd0.img CID generator

3. In the CID generator enter the ROM version you noted down and set CID to 11111111. Let it generate and download it.

4. Download flash_image binary from here and then do the following in adb while the phone is connected:

adb push /{the folder u downloaded it to}/flash_image /data

adb push /{the folder u downloaded it to}/mtd0.img /data[/code]




5. In terminal app type following:

[code]chmod 755 /data/flash_image

/data/flash_image misc /data/mtd0.img

Now the mainversion is changed, so that the we pass the RUU's version checking. 6. Type the following while you're device is connected to adb:

adb reboot oem-78

It will now reboot into RUU mode. OBS! dont panic, its supposed to just a image, nothing more. Make sure USB cable is connected to the device by:

fastboot devices

If it returns with a device, then you're good.

7. Run the RUU and let it work. Enjoy your downgraded HBOOT version.

Edited June 20, 2010 by behnaam

[Guest snear]

What's the reason for downgrading ? I'm on 7.5

[Guest behnaam]

What's the reason for downgrading ? I'm on 7.5

No need to downgrade, this is just in case HTC pushes a new hboot version that blocks the current root solution. Or in case we get a ENG SPL :)

[Guest snear]

Ahh ok thanks , good to see progress !

[Guest ice_prophey]

OBS! There is no reason to downgrade in case you already have hboot version 0.75 or a rooted 0.80 device

Just to clarify.

If I have a unrooted 0.80 device (updated officially via OTA), I should use this method to downgrade to 0.75 HBOOT then proceed to use Pauls R5 method to root a 0.75 device?

(Just want to keep my options open)

Regards,

Ice.

[Guest Arthur Hucksake]

Will this enable me to install an older rom?

I've noticed the battery life has been nowhere near as good since going from the 1.15s to the newest 1.20s, or is that down to the radio version?

[Guest EddyOS]

Possibly just radio, you could flash an old one and go from there I suppose...

[Guest EddyOS]

Just to clarify.

If I have a unrooted 0.80 device (updated officially via OTA), I should use this method to downgrade to 0.75 HBOOT then proceed to use Pauls R5 method to root a 0.75 device?

(Just want to keep my options open)

Regards,

Ice.

You can root fine using HBOOT 0.80 as I've done it myself, the files are in the root thread...

[Guest Subject Delta]

Would it be possible at some point in the future to use this method to flash a custom SPL and overcome the last bits of the root puzzle?

[Guest ElDiablo77]

Would it be possible at some point in the future to use this method to flash a custom SPL and overcome the last bits of the root puzzle?

Wh@ he said!

[Guest Kushan]

Yeah, any word on this? Would be interesting to hear from someone who knows a bit more about this stuff.

[Guest 42turkeys]

Can you do this without root?

Just wondering for all those hero users out there...

[Guest albino71]

Works like a charme! Tnx

[Guest stuart.q]

Hi there,

I am running HBOOT .80 and need to restore RUU_Bravo_Telstra_WWE_1.15.841.14_R4_Radio_32.30.00.28U_4.05.00.11_123851 which only works with HBOOT .75.

How do I enter the version number into the CID generator - it is 11 characters long and will not be accepted.

Appreciate your work,

-Stuart

[Guest albino71]

Hi there,

I am running HBOOT .80 and need to restore RUU_Bravo_Telstra_WWE_1.15.841.14_R4_Radio_32.30.00.28U_4.05.00.11_123851 which only works with HBOOT .75.

How do I enter the version number into the CID generator - it is 11 characters long and will not be accepted.

Appreciate your work,

-Stuart

Someone correct me if i'm wrong, but i think it's ok to use 1.15.504.3. The RUU will check if your current version isn't newer than the one you're gonna flash.

[Guest bllmcleod]

hi I was wondering if you could help my phone is t mobile and has 0.80 bootloader via t mobile ota update so I was wondering if I could unroot using the t mob 1.21.110.4 rom without going to bootloader 0.75. my current flashed rom is the r6 fear free one. I still have gold card, but I am very much a beginner with flashing so any help greatly appreciated, thanks in advance by Billy

[Guest ryancy]

the above method only works on rooted device? what about non rooted ones?

[Guest dodolom]

the above method only works on rooted device? what about non rooted ones?

Hi guys,

I am on the same boat. I was testing the how to unroot your phone and accidentally put the Virgin Mobile Stock Rom 1.23.xxx.x and I can not downgrade now because the method above is for rooted phones.

Any suggestions?

Thnx

[Guest ninjo]

im trying to downgrade and get ........ to' /data/flash image' : permission denied

i tried googling and people say u need a rooted android to be able to do it??

but im pretty sure when i went to try root my android it says to follow this topic before rooting if you dont meet the requirements??

please help ^^

[Guest valerebel]

How do I tell what HBOOT version I have?

Cheers

-valerebel

[Guest Restless_UK]

I get the same message as the guy below. i have 0.80 and installed the "rootedupdate.zip" to my desire. i am a little usure if it is properly rooted as i did step 1 via windows fine, and ran step 2 but has access denied at the end.. i have since been installing Roms fine using the "recovery-windows.bat" and installing from zip. i wish to install the o2 rom for warrenty but thats 0.75 boot rom so need to back track the boot version.

software:

Firmware : 2.1-updat1

Kernel : 2.6.29-82821fb5

Build : 1.15.405.4 CL155070 release-keys

Software No. : 1.15.405.4

any quick ways of confirming if it's rooted or not?

im trying to downgrade and get ........ to' /data/flash image' : permission denied

i tried googling and people say u need a rooted android to be able to do it??

but im pretty sure when i went to try root my android it says to follow this topic before rooting if you dont meet the requirements??

please help ^^

[Guest Nightowl17]

Hello,

I accidentally installed on my HTC ROM 1.22.771.1 Desire French. I no longer have access to the network with.

The HBoot of this ROM is 0.80, the Device Is Not Root.

Is what I can do something to replace the ROM with a 1.15 or 1.21?

Manipulation does not work:

/data/flash_image': Permission denied

Have you got a solution for downgrade the Hboot ? It's need to be root or not ?

Very sorry for my bad english, and thanks for your help .

[Guest yukkio]

Hello,

I accidentally installed on my HTC ROM 1.22.771.1 Desire French. I no longer have access to the network with.

The HBoot of this ROM is 0.80, the Device Is Not Root.

Is what I can do something to replace the ROM with a 1.15 or 1.21?

Manipulation does not work:

/data/flash_image': Permission denied

Have you got a solution for downgrade the Hboot ? It's need to be root or not ?

Very sorry for my bad english, and thanks for your help .

If you get permission denied I think this method is for rooted devices.

BR.

[Guest rhedgehog]

If you get permission denied I think this method is for rooted devices.

BR.

I find that it did not work when I tried using a terminal app on the phone itself, i would get permission denied errors.

However, i instead did it in shell in adb.

so

instead of typing the two commands in a terminal program on the phone, type ' adb shell ' in the same window you issued the previous adb commands

enter the two commands

type exit to exit the shell

carry on with the adb reboot oem-78 command

that worked quite happily on a non-rooted, 1.21 phone.

now downgraded back to 0.75 bootloader allowing me to install the older rom i need for testing at work.

[Guest kaska_pt]

any chance this works on the Legend with some changes or so? bootloader 43.0003...