You might read the original topic if you are good at Chinese. We are the first to crack GT420M on OS X 10.6.5.
ACER ASPIRE 4741G
CPU: Intel Core i5 430M
Graphic card: NVIDIA GT 420M 1024MB
Wifi: AR5B97------not working, already replaced with AR9280
software and driver required:
1. Chameleon v2.0-RC5 r650
2. Nividia drivers geforce 4xx+580 (tweaked by tony) ： （NV Mac OS X Driver Release_256.01.00f03 also works, but you need to install it through 3 packages which are extracted from the original pack）
3. Moded DSDT.AML for Acer 4741G
1. install Chameleon v2.0-RC5 r650
2. install Nividia drivers geforce 4xx+580 (tweaked by tony)
3. go find GeForce.kext and NVDAGF100Hal.kext in Extensions folder，then right kick each and modify the info.plist by inserting the GT420M ID. By the way, my GT420M ID is 0x0df110de：
save both after modifying.
4. Copy the attached DSDT.AML to Extra folder and modify com.apple.Boot.plist by adding 2 lines into it as follows:
5. Disk tool------->repair disk permissions. Then restart your computer and see if it works.
DONE. You might also try it on GT425M or GT445M to see if it works.
PS: Some friends tried this method and found that it could still drive GT420M even if GeForce.kext and NVDAGF100Hal.kext were not modified with hardware IDs.