Default [Q] Any way to gain write-access to SD on 4EXT Touch Recovery?

My phone (Evo 3D CDMA) got corrupted and stuck in a bootloop. This has happened before (more often than I care to count) and I know how to fix it, but it requires temporarily moving some files on the SD card and editing a backup made by 4EXT Recovery.

Problem is, I don't currently have access to a SD card reader. I tried mounting the SD card as USB Storage on a desktop PC, but while I could read it just file, Windows complained that I had no write-access when I tried to move, delete, or edit any files.

I looked and Googled everywhere but couldn't find information on 4EXT mounting USB Storage as read-only or gaining write access. Is there any way to write to the SD card over 4EXT?