I googled and couldn't find anything to post, so I didn't. I use OSX and never really bothered to trim my gba roms so I don't know of any program that does it. You can do it yourself using a hex editor as described
here. I use "HexEdit" which is a PPC app available on sourceforge.net somewhere. It should work on intel macs also, but don't quote me on that.
Unfortunately, that looks to be the only solution.
EDIT: As I wrote the original post I was thinking about
uCON64 but didn't think it stripped roms. Well it turns out that it does. BUT-- it's a terminal app and most OS X users hate that blasted terminal
To strip your gba roms using uCON64, you have to run it twice from the terminal, once to find out the amount of bytes padded and next to remove the padded bytes. I will show you step by step, the commands with a Super Mario Advance 4 rom.
(I'm using WinXP right now, but the program works the same reguardless of OS)
First put the binary either in your /usr/local/bin, /usr/bin, or in the directory with your roms.
I'm assuming you know the basics of the bash command prompt so I'm not going to tell you how to invoke the program based upon where you decided to put it...
will spit out all of this:
CODEuCON64 2.0.0 Win32 (MinGW) 1999-2005
Uses code from various people. See 'developers.html' for more!
This may be freely redistributed under the terms of the GNU Public License
C:\sma4.gba
Flash Advance Linker
00000000ÂÂ2e 00 00 eaÂÂ24 ff ae 51ÂÂ69 9a a2 21ÂÂ3d 84 82 0aÂÂ....$..Qi..!=...
00000010ÂÂ84 e4 09 adÂÂ11 24 8b 98ÂÂc0 81 7f 21ÂÂa3 52 be 19ÂÂ.....$.....!.R..
00000020ÂÂ93 09 ce 20ÂÂ10 46 4a 4aÂÂf8 27 31 ecÂÂ58 c7 e8 33ÂÂ... .FJJ.'1.X..3
00000030ÂÂ82 e3 ce bfÂÂ85 f4 df 94ÂÂce 4b 09 c1ÂÂ94 56 8a c0ÂÂ.........K...V..
00000040ÂÂ13 72 a7 fcÂÂ9f 84 4d 73ÂÂa3 ca 9a 61ÂÂ58 97 a3 27ÂÂ.r....Ms...aX..'
00000050ÂÂfc 03 98 76ÂÂ23 1d c7 61ÂÂ03 04 ae 56ÂÂbf 38 84 00ÂÂ...v#..a...V.8..
00000060ÂÂ40 a7 0e fdÂÂff 52 fe 03ÂÂ6f 95 30 f1ÂÂ97 fb c0 85ÂÂ@....R..o.0.....
00000070ÂÂ60 d6 80 25ÂÂa9 63 be 03ÂÂ01 4e 38 e2ÂÂf9 a2 34 ffÂÂ`..%.c...N8...4.
00000080ÂÂbb 3e 03 44ÂÂ78 00 90 cbÂÂ88 11 3a 94ÂÂ65 c0 7c 63ÂÂ.>.Dx.....:.e.|c
00000090ÂÂ87 f0 3c afÂÂd6 25 e4 8bÂÂ38 0a ac 72ÂÂ21 d4 f8 07ÂÂ..