update from old current (october) to 9.0 beta fails in installworld

Hello,

Looks like I've broke my soekris net5501 while doing installworld (built
with clang)

===> libexec/rtld-elf (install)
chflags noschg /usr/libexec/ld-elf.so.1
install -s -o root -g wheel -m 555  -C -b -fschg -S ld-elf.so.1 /libexec
install -o root -g wheel -m 444 rtld.1.gz  /usr/share/man/man1
*** Signal 4

Stop in /usr/src/libexec/rtld-elf.
*** Error code 1

# ls
Instruction interdite(core dumped)

(instruction interdite => illegal/forbidden instruction)

Are there known issues for updating (I didn't follow the single
user step to install the world, as usual, because the box is only
reachable via ssh)  ?

Thanks for 9.0, looks nice.
Regards.