I just did some tests and the culprit seems to be my 4K TV screen. I've got no problem on my 1440p PC monitor.

@iw2lsi third party images are not supported here. Ask the image creator for help. Or use the official image if you want support here.

OK I don't know if this is the best way of doing this but it seems to be working. The new config files were saving to configs/all/retroarch/config. The retroarch file being looked at is in gba/retroarch.cfg. I simply copied the content of the new config file and overwrote the content in retroarch.cfg with the new data. I kept back ups of the original files in case anything goes haywire. So far it seems to be just fine. Thanks.

@meleu: I've added version in my initial post (sorry to have not posted this earlier)

@jdrassa: the scrolling was restarting at the beginning but you point me to the right solution. By disabling Power Saver Modes in EmulationStation option, the scrolling is perfect as before now (goes to the bottom, pause for a sec or 2 then start from the beginning).

Thanks for your help.

yay i did it but i still want to know about that buffer problem