digi(4) panics 5.3-BETA6

I've just tried loading 5.3-BETA6 onto a HP DL380 that has a DigiBoard
Xem and found two (critical for me) problems.  I've upgraded to just
before BETA7 (I'll try upgrading again tomorrow) with no change.

Problem 1:  Using tip on a Digi port causes an instant panic dereferencing
  a NULL pointer.  The critical part of the backtrace is:
#23 0xc05f6507 in knote (list=0xc2850080, hint=0, islocked=0) at atomic.h:365
#24 0xc063fbcd in ttwakeup (tp=0xc2850000) at /sys/kern/tty.c:2370
#25 0xc063e830 in ttymodem (tp=0xc2850000, flag=0) at /sys/kern/tty.c:1625
[called from digiopen]

(kgdb) p *(struct tty *)0xc2850000
$2 = {t_rawq = {c_cc = 0, c_cbcount = 0, c_cbmax = 77, c_cbreserved = 77,
    c_cf = 0x0, c_cl = 0x0}, t_rawcc = 0, t_canq = {c_cc = 0, c_cbcount = 0,
    c_cbmax = 77, c_cbreserved = 6, c_cf = 0x0, c_cl = 0x0}, t_cancc = 0,
  t_outq = {c_cc = 0, c_cbcount = 0, c_cbmax = 22, c_cbreserved = 22,
    c_cf = 0x0, c_cl = 0x0}, t_outcc = 0, t_line = 0, t_dev = 0xc284bc00,
  t_state = 131080, t_flags = 0, t_timeout = 0, t_pgrp = 0x0, t_session = 0x0,
  t_sigio = 0x0, t_rsel = {si_thrlist = {tqe_next = 0x0, tqe_prev = 0x0},
    si_thread = 0x0, si_note = {kl_lock = 0x0, kl_list = {slh_first = 0x0}},
    si_flags = 0}, t_wsel = {si_thrlist = {tqe_next = 0x0, tqe_prev = 0x0},
    si_thread = 0x0, si_note = {kl_lock = 0x0, kl_list = {slh_first = 0x0}},
    si_flags = 0}, t_termios = {c_iflag = 0, c_oflag = 0, c_cflag = 19200,
    c_lflag = 0,
    c_cc = "\004ÿÿ\177\027\025\022\b\003\034\032\031\021\023\026\017\001\000\024ÿ",
    c_ispeed = 9600, c_ospeed = 9600}, t_winsize = {ws_row = 0, ws_col = 0,
    ws_xpixel = 0, ws_ypixel = 0}, t_sc = 0x0, t_column = 0, t_rocount = 0,
  t_rocol = 0, t_ififosize = 512, t_ihiwat = 7680, t_ilowat = 6720,
  t_ispeedwat = 0, t_ohiwat = 1296, t_olowat = 256, t_ospeedwat = 0,
  t_gen = 0, t_list = {tqe_next = 0x0, tqe_prev = 0x0}, t_mtx = {mtx_object = {
      lo_class = 0x0, lo_name = 0x0, lo_type = 0x0, lo_flags = 0, lo_list = {
        tqe_next = 0x0, tqe_prev = 0x0}, lo_witness = 0x0}, mtx_lock = 0,
    mtx_recurse = 0}, t_refcnt = 0, t_hotchar = 0, t_dtr_wait = 0,
  t_oproc = 0xc2810fa8, t_stop = 0xc2811210, t_param = 0xc28105a8,
  t_modem = 0xc280f488, t_break = 0xc2810548, t_ioctl = 0}

Problem 2: The system won't reboot.  It hangs after the 'rebooting' prompt
  and needs to be powered off/on to recover.  Disabling ACPI has no effect.

Has anyone else seen either of these problems?
-- 
Peter Jeremy