I don't think that this is possible in the way you state.
What you want is to set the vga mode. Assuming you use lilo, you will have a stanza somewhat like this:
## Debian SID
Change the vga line to vga=ask
Now, from the lilo.conf man page:
This specifies the VGA text mode that should be selected when
booting. It may be specified as a global option. The following
values are recognized (case is ignored):
normal: select normal 80x25 text mode.
extended (or ext): select 80x50 text mode.
ask: stop and ask for user input (at boot time).
<number>: use the corresponding text mode. A list of available
modes can be obtained by booting with vga=ask and pressing
If this variable is omitted, the VGA mode setting contained in
the kernel image is used. (And that is set at compile time using
the SVGA_MODE variable in the kernel Makefile, and can later be
changed with the rdev(8) program.)
So if you change this, or add the vga line if you don't have it, you can experiment with modes and the "hardwire" the one you want - or leave it at ask.
Run /sbin/lilo after editing the file.
I have a vague memory of having once seen this in action but haven't tried it. You might like to duplicate one of your existing stanzas (with a different identifier) rather than edit the existing one. It will make recovery easier is something goes wrong.