Successfull install of 5.2 on AS600, some problems remain

[M. O.]

1. Successfull install of 5.2 on AS600
I finally achieved to install FreeBSD on an alpha-station 600 5/333.

As far as the internal CDROM didn't read burned CDs, I tried for 2 weeks 
to install from floppies.
FreeBSD 4.8 was the only bootable version but hangs after SCSI 
peripherals detection (though I preloaded ispfw for the Qlogic ISP 
ultraWide card, I upgraded the SRM firmware to 7.2.2, I set the isp_mode 
from fast to ultra, I set isp_mem_map=0xff as shown in HARDWARE.txt).
Other releases alpha floppies causes SRM to return "not a correct boot 
sector".

I took an old cd-buner (4x writespeed max), wrote a freebsd5.2-disc iso, 
and the as600 cdrom read it! I think that the bunch of modules (even 
uselessly loaded ones like usb) helped.

2. remaining problems
a. Some tools coredump, for example  :

/usr/bin/top : Segmentation fault (core dumped) and gdb /usr/bin/top 
top.core says :
(gdb) bt
#0  0x1602464c8 in strlen () from /lib/libc.so.5
#1  0x1601e79b4 in getpwent () from /lib/libc.so.5
#2  0x1601cdf18 in yp_next () from /lib/libc.so.5

May be a bug in Nis ?

b. Some modules hangs (the console , the kernel ?)
b1. Screen saver modules hang the kernel (no more ping nor keyboard) :  
Is the TGA graphic card responsible?
b2. The freshly built kernel detects the PCI FDDI nic.
partial dump of pciconf -lv :
fpa0 at pci0:7:0:  class=0x020200 card=0x00000000 chip=0x000f1011 rev=0x00 
hdr=0x00
    vendor   = 'Digital Equipment Corporation'
    device   = 'FDDI "DEFPA"'
    class    = network
    subclass = fddi
But ifconfig on fpa0 crashes the kernel.

c. Text consoles is broken after running X.
The text consoles are in a bad refresh mode when switching from X 
(Alt-F9) to text (F1-F8).
Should I find an other video card or switch the TGA 8bit planes to 80x25 
text mode with allscreen_flags?