yaboot not boot (macosx dual boot config with fedora)

[haalaa luu]

hi greeks,

- Fedora Core 4 (t3) text mode installation
- sdb3 /, sdb2 bootstrap, sdb4 swap (lower bay
hd,linux only on drive)
- sda3 macosx (entire hd is macosx tiger)
- yaboot just flikr a second and only
macosxboot(loginscreen) appear
- powerpc g5 dual 2ghz, second gen, radeon 9600, 1g
ram
- currenly, i can access through rescue mode to shell

pls help me i couldn't sleep about two days, thks :(