Hello,
its possible to adjust Windows 98 behavior to not boot to Safe mode as default after crash? Its annoying, because my version crashing often and i can you USB device in safe mode, so safe mode is useless for me.

Doesn't Windows reboot automatically in safe mode by default only after failing to fully boot?

Anyway you need to edit the msdos.sys file in the system drive root dir to set those kind of boot options.
 

My machine is working this way - crash, reboot - i got system protection error, reboot - safe mode is default - reboot - scandisk and normal boot - Its annoying, i dont know if is QEMU or Win98 fault, but too much rebooting.

In msdos.sys, try those options:

[Options]
Autoscan=0
BootMenu=1
BootMenuDelay=5

Scandisk will not run automatically and you'll always have a boot menu displayed with 5 seconds to change the automatically selected boot mode. 
 

In msdos.sys how do you mean it? I suppose msodos.sys is not text file, or im wrong?

msdos.sys is a simple text file indeed.
 

Quote

msdos.sys is a simple text file indeed.

Great to know, was using 25 years config.sys, but i never though that msdos.sys is same sort of beast.

Hmm, this is not solution.. i still got error windows not finish loading error and default boot option after that is still 3.

Well this won't eliminate your windows loading error as this is likely either hardware or driver problem, it just allows you to conveniently intercept boot mode options and manually change it to normal if you wish so, best you can do I am afraid.