I tried disassembling the HDPro installer before - but I remember getting stuck because I can't decompress/de-scramble it.
Yes, this ELF is scrambled and/or compressed in some funny way (Not with PS2-packer).
I can't proceed unless it's decompressed and/or de-scrambled.
EDIT: My bad. I kept forgetting that there was an ancient PS2 executable compressor called "sjcrunch" (So I used sjuncrunch to decompress it).
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS