Thanks to ZZMT, I also already did 0'46"73 at PC, 0'42"66 at BC1, 1'21"68 - 25"33 at BC3, 0'46"13 at Retro MC1, 0'58"21 at Retro DP1

, 0'42"38 at Retro CI1 and 1'10"26 at Retro DP2 !
And without ZZMT, 7"07 at Retro GV1.

If you have a GBA SP, it's not too hard to dismantle it, you just need the Triwing screwdriver, findable on eBay (dunno about GBA). It's the same screwdriver for DS and DS Lite, except for the battery's screw, where you need a very little cruciform screwdriver. But I still haven't it, so I haven't dismantled DS to help DS users if they want ZZMT.