[myTouch 4G General] thebrownfan80:
I got my mytouch 4g (running 2.3.4) on october 6th 2011. i had it for a month and a half before deciding to root. I am not sure what chip i had, but this is what happened:

I decided to root and had a friend help me do it.

We followed the downgrade guide and got every step to work except the md5sum check, but it still booted into froyo even skipping that step. from there i rooted using the gfree method posted on youtube by mackster. after rooting i installed clockworkmod recovery via rom manager. then flashed cm7.1 stable via CWM. Everything was going fine (except that launcherpro would FC when it first started everytime i rebooted the phone, the only problem i had prior to meltdown day). I rebooted the phone daily as I read was good to do on one of the cyanogen forums.

Then one day I decided to try the stock CM7 adw launcher since launcher pro kept forceclosing on me. I switched back to adw and started downloading adw themes from the market. On about the 5th theme the phone went nuts when I tried to apply the theme (can't remember which theme it was). Suddenly I got ADW forceclose message and launcherpro forceclose message popping up over and over one after the other. I couldn't get back to the homescreen, force close and black statusbar dropdown were all that would show. I pulled the battery because the power button was unresponsive.

After the battery pull the phone would freeze at the boot image. I battery pulled again and restarted holding down the volume down and power button. in recovery i got the cache mount errors in cwmod. tried to wipe the cache and data, but both were not found. Tried to restart the phone and the recovery but both led to boot image freezes. Tried to flash pd15img but that didn't work either. finally my phone fully bricked after something or other that i did, and now waiting on the replacement.

I don't know what chip i had because i only found this thread (and other emmc info) after googling the image code CWM gave me after the failure.

Why don't the many rooting guides i looked at warn to check the emmc before rooting???

I will be sure to check the emmc before rooting my replacement phone, but it would have been nice to at least know if the emmc is what killed my last phone.

I only flashed one rom, and it was working fine for a month before dying, so i don't know if i did something wrong to kill it or if it was the chip.

The only thing that i was unable to do while rooting or downgrading was the downgrade md5sum check from the cyanogenmodwiki downgrade/root guide. everything else i did 'by the book'.

what is the md5sum check and what does it do? was it bad that i skipped it? might that have caused my errors later?

this is my first android phone, so i'm new to all of this, but the guy that helped me root it has rooted a few phones before. he said this was the hardest phone he ever tried to root.

the guides that i read for downgrading/rooting didn't explain very well about the md5sum portion of the process and there were little resources i could find explaining anything about it using a google search, so i'm asking about it here to try and figure out how i went wrong with my last phone.

thanks.