Hi Juanito is in a different time zone so if possible please be patient
Until you get a better reply
In the meantime as I can not use vesa myself but can use xorg you may like to see the wiki which says
http://wiki.tinycorelinux.net/wiki:display_modesand it appears your 1600x900 is not supported.
2) are you on x86 (32 bit) or x86_64 (64 bit)?
you may like to try xorg and one of GUI packages that might assist you but not sure if it will do 1600 x 900 is
*randr
search your Apps for randr.....in 64 bit you will see a few hits and the GUI Apps all relate to having Xorg set up.
But that may not suit you.