Having gone through such stage (bricked my Lumia 1020 about 2 months ago). I know the longing to get things working again. You wish to rollback in time.
In my case, I was 'again' upgrading my device to Windows 10 Mobile. Using WPInternal's because Windows Phone 8.xx.xxx has almost reached the end of its journey. I'm missing so many awesome apps which are being gradually knoced-out from the WP8 platform. It almost looks like virtual-suicide to me. This is happening in Win 10 Mobile platform, but more slowly.
Anyways, How/why my LUMIA 1020 got bricked
- Somewhere during flashing I heard USB Disconnect sound.
(Felt f**ked up) LoL.
- Followed by Windows message - "WPInternals not responding"
- I confirmed that My Lumia is (was) bricked. Nothing on screen, no vibration- No direct signs of life (Direct I'm saying). I behaved as you did, cried to god also :P
USB Port on my Lumia was not working properly. Actually, it worked at a critical angle flipped down, strange, but working. I tried to clean port with alcohol, took out some micro fibres stuck inside. But it don;t want to be normal + Data cables at my disposal were too old to be working with that
Loose USB Port* - This might(99.99%) have caused diconnection during flashing operation resulting in Bricked Phone, in my case
I had never seen a bricked phone in my life, before. So, I wanted to know why this happened.
(Telling you this because if solution below doesn't work & you still want to revive it, keep digging. Otherwise buy a new phone if you can)
This 'might' work only if you are getting QHS_USB_QDLoad (or something similar) in your Device manager. i.e.- Device manager should be detecting your device (even for 1 second, as in my case)
Install Windows Device Recovery Tool (WDRT) from here
Also, Download the "Emergency files" for your phone from LumiaFirmware.com. Search/Browse from the list your RM-94x - Lumia 625
It is very important to choose correct RM-94x for your device. Otherwise you might face other terrible problems.
Select appropriate Product code from the list shown on right for related RM-94x
I've choosen RM-875,etcetra here as an example. If you're having problem finding your product code, try googling or ask someone, before proceeding
Download & Save all the Firmware Files and Emergency Files (Marked in Blue Box)
Skip Firmware files if you are having Firmware downloaded already from WDRT or elsewhere.
Save all the 'downloaded files' in single-folder in ...\Products\RM-94x\ directory
Make sure to CHARGE YOUR DEVICE ATLEAST 1-hour before proceeding, even if its not working
(e.g.: I've RM-875 in my case, in Downloads\Products\RM-875)
- Launch WDRT (You should have working internet connection as s/w looks for updates)
- Go to Settings>Packages> Set 'Use custom path packages' to ON and browse upto the folder where 'Products' is located. and Restart WDRT
If WDRT not selected automatically, Select- My device was not detected (Since your device is bricked it won't be detected by WDRT, probably)
Your Device will appear as "RM-94x blah!". Select it.
Tadaa!! Let the WDRT do its job. Do-not-Disturb anything.
Flashing in Windows needs switching to Emergency Download Mode, that's why we needed Emergency Files.