Phone will no longer connect via USB after bad ROM I have a phone that was flashed with a bad ROM. It no longer has a system, so actually getting into the phone is a no-go. It can, however, boot into recovery and download mode. I planned on flashing to a stock ROM, but I can no longer connect via USB: Windows simply cannot recognize the device. 

I've gone through various driver installations, but to no avail. I figured I'd give up on the USB and just put a stock ROM on an SDcard and install it through recovery. Would this work, or do I need to do it through USB?
With these things there are always exceptions and a few clever work-arounds, the below is general advice.

Only flash a ROM for your exact device model

You can't flash something not 'stock' through the stock recovery, attempting to do so will cause signature errors. The opposite; flashing stock ROM through a custom recovery will also error. So you will not be able to restore to stock first (more than likely anyway.)

However, since you don't immediately need the phone on stock, then you can copy any ROM compatible with your device onto the SD card and flash that through recovery. At least then you will be have a booting device, and can deal with the USB drivers issue. 

Installing in recovery would usually involve the 2 main steps below:

Wipe the device
Install from zip

And then install any other zips you may need (e.g. google-apps). 

You could attempt to mount the SD card in your recovery but I'd guess you've tried all those options.

Also as Izzy has pointed out you may need a new radio-firmware flashed on the device to allow "low level interface" connection, so the kernel has nothing to connect to. 

Once again ONLY flash something for your EXACT device or you will have a shiny paper weight!