You need a file called opening_plugin.rco and edit the duration with RCO Editor.
Here is a download for RCO Editor
http://www.mediafire.com/file/z53ul6bb0jmuwog/RCO+Edit.rar, includes a gameboot and a opening_plugin.rco, you can use the opening_plugin.rco with your gameboots, you only need to change the duration following the next steps:
1.- Open the opening_plugin.rco with RCO Editor.
2.- Go to Anim Data Tab.
3.- On the Left chart, look for
anim_gameboot_movie @ 0x32BC.
4.- You will see in that section that there are three
[0x907] Delay parameters, Choose the third one.
5.- The Right chart indicates the value of the parameter, in this case it shows the duration of the gameboot in miliseconds, You can change that value by double-clicking it.
6.- Close RCO Editor, It'll save the changes automatically.
7.- Now copy your edited opening_plugin.rco in the same folder as your gameboot.
I don't know if MyBoot Logo plugin is compatible with opening_plugin.rco files, if is not compatible, you can use another plugin like
ZeroVSH Patcher.