Recover soft bricked Nexus 4 using download mode

My nexus 4 is bricked and it all started with a bootloop. Although I can get into recovery mode, it doesn't let me flash anything and throws flash write failed errors for everything. Also when I boot into twrp recovery I get unable to mount /data, /system, /recovery, /cache errors for every action I perform. Formatting the partition also throws same errors. I have tried everything from reflashing factory ROM to CW11 ROM. In all probability it appears that the file system/partition table is totally corrupt and flash is unwritable. When I do fastboot oem unlock, it successfully unlocks the bootloader only until the next restart. After restarting, it is again locked, another sign that flash is unwritable. Now my only hope left is the download mode...please tell me how I can recover my phone using download mode or is there any other way.

Its been 4 frustrating days trying to resurrect my phone, all in vain. Please help!!

jd1639 said:

It sounds like to me that your emmc is bad. Do you still have warranty? I highly doubt you'll be able to fix anything

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No I don't have warranty, but I am trying the download mode using LGNPST outlined here http://xdaforums.com/nexus-4/general/tutorial-how-to-unbrick-n4-t2347060
Do you think it can work?

jd1639 said:

If anything can that will, but if your emmc is bad nothing is going to work.

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I sent it to the LG service center, they said it would require a motherboard replacement that will cost me probably more what the phone is worth right now. Is there anything that could be done to save my phone? Is the emmc replaceable?Also doesn't the fact that I can boot into fastboot, mean that the hardware is good. Isn't the bootloader stored on emmc?