i bricked 2 ez4s somehow in a similar circumstance. i think i was testing the ram with image viewer (running from slot one card, p.s don't do this the ram usage fails this way as i also discovered).
1 is almost completely dead (not recognised by DS main menu, only ram still works, but sram doesn't (req for saving games with 2in1 tool (see below))
fortunately the other (which i had only bought to replace the bricked one, and i repeated the same mistake!) although it doesn't boot (it is recognised but white screen), i can load gba files through Rudolph's EZ4 2in1 Tool and still use the ram with opera and homebrew.
Also it's useful that with both i can still access the SD card memory through DLDI apps.
I suggest you attempt to use this functionality - running apps from slot one patched for SC slot 2 for extra memory.