For those of you who have rooted your HTC Evo and have been messing around with different ROMs on your HTC Evo 4G, you know you can use ROM manager but there’s also another way, by unlocking Nand protection and installing the recovery menu permanently. (Thanks to XDA Developers!)
I tend to like the latter option better because it has Nandroid, I like the Nandroid backup/recovery.
By installing this mod, you should/be able to backup/restore different ROMs on the go. (Also you can do it with ROM manager of course but ROM manager doesn’t work under unrooted ROMs so you’d have to go back to command line method.)
First, let’s backup your current ROM (whatever you are using) by using command line and Nandroid. Because we will have to “downgrade” your ROM in order to unlock the Nand protection.
Second, you will want to download these 4 files:
Next, unzip both mtd-eng.zip and flash_image.zip, which will get you mtd-eng.img and flash_image.
Connect your HTC Evo 4G to your computer, choose “Disk Drive”, then copy the files mtd-eng.img, flash_image, recovery.img and PC36IMG.zip to the root folder of your HTC Evo 4G’s SD card.
Change your HTC Evo 4G to “Just Charge” mode because we will need to access the SD card from ADB shell.
Go to your SDK Tools folders (where you installed Android SDK such as C:\sdk\tools), then type “adb shell“.
Next, type in the following three commands:
cat /sdcard/flash_image > /data/flash_image chmod 755 /data/flash_image /data/flash_image misc /sdcard/mtd-eng.img
Now, turn your phone off and reboot it into hboot/bootloader by pressing the Power button while holding down the Volume Down button.
Wait about a minute or two and your Evo 4G should ask you if you want to update the zip file. Say yes by pressing the Volume Up button.
When it’s done, hit the Volume Up button again to reboot.
After you reboot, choose “Disk Drive” for your Evo 4G, then erase the PC36IMG.zip file as we don’t need it anymore and your phone will try to update it again when you go back into the hboot/bootloader mode.
Next, set your HTC Evo 4G as “Charge Only” again and go back to the SDK Tools folder, then type “adb shell” again.
cat /sdcard/flash_image > /data/flash_image chmod 755 /data/flash_image /data/flash_image recovery /sdcard/recovery.img
(*Note – I got an error message that it couldn’t write a block but I think you can ignore it as my Recovery menu is working just fine now.)
Congratulations! Now you’ve officially unlocked the Nand protection and you can access the “new” Recovery menu to backup/restore/flash new ROMs!!!
Turn your HTC Evo 4G again then press Power button while holding down the Volume Down button.
Select “Recovery” using your Volume keys then hit the Power button.
You should have arrived at the new Recovery Menu. You can always enter this new Recovery Menu to flash/backup/restore new HTC Evo 4G ROMs.
Now, let’s restore your previous ROM before we unlocked the Nand protection so choose “Backup/Restore”, “Nand Restore”, then locate your last backup. (It’s organized by date.)
Restore your previous ROM, reboot, and voila!
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