In Solaris 2.4 a bug was introduced that makes tftpboot chroot, while it still needs to open a socket. The first request still gets a response, but all other requests meet with a 5 second delay.
Workaround:
mkdir /tftpboot/dev mknod /tftpboot/dev/udp c 11 41 chmod 755 /tftpboot/dev; chmod 666 /tftpboot/dev/udp
This is fixed with patch 102773-01 (sparc) and 102774-01 (x86).