[myTouch 4G Android Development] ckisgen:
Very important - read all of it - this could save your phone

yep .. i was walking someone thru trying to get their device back alive last night for over 4 hours .. he didn't have engineering hboot .. his phone is still a soft shell crab .. for now .. i am still optimistic that we can get it back but there are no guarantees.

so far, there's just no way to get at the /system partition to erase, write, or otherwise with a locked bootloader (with this particular issue). he is even rooted/s=off via g-free .. all attempts thus far even to get bootloader to reflash the stock PD15IMG have been unsuccessful ... though if you're on 2.3.x ROM (and presumably CWM 3.0.2.4 or 3.0.0.6, etc) and this happens, you REALLY need to exhaust ALL options on trying to restore/reflash/recovery.img etc FROM A WORKING 2.3 ROM first before trying the PD15IMG route ... that's what i've gathered so far from the 5-10 hours of exhaustive research i've done so far on this issue and issues very similar

from what i can tell - he was using some other backup/restore app from the market (trying to find the name again now so i can warn you guys to stay away from it) and i'm pretty sure that it restored some system data or data to clockworkmod from a previous version and somewhere in the process after a full wipe - it fried his system block partitions

most of the other people across various forums/platforms/ROMs that have experienced this or something very similar (can't mount cache/recovery error in recovery .. along with other symptoms that won't allow you to mount/format system, etc) mostly either accidentally flashed a ROM that wasn't meant for the recovery that they were on (like trying to flash a Froyo based ROM on a Gingerbread only recovery, etc) ... or they had restored SYSTEM or CWM data at some point from titanium or other various backup/restore programs

bottom line being .. MOST of the users that i saw with locked bootloaders (0.86.0000 on our device) have not been able to recover from a truly screwed / unwritable system block

on the other side of that, MOST if not all of the people I found that DID have engineering hboots (0.85.2007 on our device) when this happened were eventually able to bring their devices back

GET YOUR ENG/UNLOCKED HBOOT if you haven't already AND BE VERY VERY CAREFUL WHEN USING BACKUP/RESTORE PROGRAMS!! (until someone figures out more EXACT causes for this - my advice is DO NOT under any circumstances restore app OR data or anything that has to do with clockworkmod / rom manager OR any system data or apps ... you could accidentally restore data or an app from an older build/version and screw something up)

most ROMs (CM7, RoyalGinger, etc etc) that I've seen have ROM manager built in .. which is fine. all of your important ROM manager / CWM related data and backups are stored on your SD card .. just make sure you have a good backup to your computer and/or another source of your clockworkmod folder from your SD card (along with the rest of the contents really ..) AND your Part7backup-numbers.bin file if you rooted g-free!!

<<as always, i cannot be responsible for anything that happens to your device and i don't claim to be an 'expert' on bringing problematic/not booting devices back to life .. i've only recently begun my journey into the depths of the interwebs to try and find out everything i can about the causes and solutions to these issues .. but i have learned a great deal over the last several days/weeks about it and am simply trying to share what i've observed from my own and others experience....like ANY advice from ANYWHERE on ANYTHING - use your OWN head, do your OWN homework, and ultimately make your OWN decisions>>