UPDATE: I "fixed" my issue by disabling plymouth in kernel params. I changed my grub file with the following: GRUB_CMDLINE_LINUX_DEFAULT="noplymouth video=SVIDEO-1:d"
After this change my computer booted normally (w/o plymouth of course) but now both monitors work and I can change my display's brightness.
UPDATE: I "fixed" my issue by disabling plymouth in kernel params. I changed my grub file with the following: GRUB_CMDLINE_ LINUX_DEFAULT= "noplymouth video=SVIDEO-1:d"
After this change my computer booted normally (w/o plymouth of course) but now both monitors work and I can change my display's brightness.