Are you using AKAIO or the official menu? Is the EZFlash V the same thing as the EZFlash 3-in-1 and if so are you using the + version (EZFlash 3-in-1+)? If so, you will want to use AKAIO (EZFlash 3-in-1+ isn't supported by the official menu as far as I know, but should work with AKAIO 1.4).
as bri stated you are probably useing the 3-in-1+, which is the newer card that has the blue pcb. the ram detection routine is in akaio as of v1.4. you just update your firmware inorder to use the opera browser and your 3-in-1+ as a ram expansion. if you are unsure what version of the 3-in-1 you have run gba exploader. it will detect the version and tell you at the top of the screen.
if you don't have the plus then you have a whole other set of problems, some of which can be solved.
The new EZ5 open beta kernel was released with a slight change, setRomPage is now to 0x100 instead of 0x300 and apparently it is now working on 3in1plus...
If someone feels like giving it a try with a standalone patch and a new 3in1+ http://nds.cmamod.com/ez5/CZ-O31Pp-test2.zip
it'd be appreciated. If it works, see if it crashes out in use as apparently EZ5 and 3in1+ are doing so though that may come down to beta ROM patches and such. It seems to be working flawlessly still on my own (old, first model) 3in1 using R4 1.18 and this version of the patch (so it should be safe to merge that minor change to the page for ak.)
Has gelu fixed this? I still see SetRomPage(0x300) in the AK3in1 menu current sources, and AIO has never resumed from lid close on opera for me... so probably not. I'm not so sure the retail card with the retail expansion would be able to sleep properly anyway because of the wifi (kudos to the engineers if it does indeed.) Basically how the lid switch is handled in commercial code is beyond me, but dredging through essentially homebrew to figure out the enable routines isn't so far out of reach
(so maybe not flawlessly in that light, but I'm not about to start patching things that the launcher should be handling anyway.)
If you get a 3in1+ change this line of the cheat
And it should work in R4 v1.18+yasu's R4 fix/YS Menu. If you are using the latest AIO, it should work without any cheats.