tried l-o-eras and dosflash but didnt work as the drive does not show up in dosflash
What do you mean by "not showing up"?
Did you re-install the VIA drivers of the 6421 card before booting to iprep? If not, you might wanna do that and try l o eras again.
Before you boot to iprep, remove all other sata or IDE drives. Just leave your main Hard drive and the liteon 74 connected.
I assume you know how to create your iPrep bootable drive with the l-o-eras instruction in it.
so let's do this.
1. boot to iprep with the liteon drive powered off
2. turn lite on ON
3. type l-o-eras.exe (and the port number your Lite On drive is connected to. It is very important that you take note what port is it because you will need it later. Usually is dd60 but you need to check) so it should look like: l-o-eras.exe dd60 hit enter and you should see FF80
4. type l-o-eras.exe dd60 you shouuld see FF72
5. Turn OFF the Lite On
6. With the Lite On OFF type dosflash and hit enter.
Now, you should see a list of drives. But Remember, you will not see the Lite On drive being described by Name or model number. When you see the list of drives, you need to look for the port number your Lite On is connected to (check step #3 above). The drive description should be something like the Port Number and say something like "Pri Master ATAPI No identify possible".
So it should look like this "6) dd60 Pri Master Atapi No identify possible"
7. hit "y" then enter and see status 072
8. Power ON the lite on drive
9. enter the list number of your ATAPI/Lite on drive. It is usually 6 but check the enumeration. So enter the number and hit enter
10. then enter "e" to erase and hit enter
11. turn OFF lite on drive
12. type dosflash and hit enter
13. "y" hit enter and see status 80
14. Power ON lite on and see status 72
15. enter the drive number as you did in step 9 above
16. type "w"
17. type "lite_cfw.bin" hit enter
18. let iprep write to the 4 banks and done.