CPU-3m not booting

[tytos]

Hello everyone,
I recently purchased a second-hand Alcatel-Lucent OmniPCX Office Small with a CPU-3m board (manufacture date 2020).
Current situation:

The system responds to ping on the default IP (192.168.92.246)
Power LED is green, CPU LED is blinking green
HTTP/HTTPS returns error 503
FTP connection times out
Serial console shows nothing (tested at 9600, 38400, 115200 bauds, 8N1, no flow control)
OMC 60.0.32.1a gives "SOAP login error - Error code 29" then "FTP connection establishment failed"

What I tried:

Factory reset using DIP switches (SW1+SW2 ON, then all switches ON)
Multiple password combinations (pbxk1064, mtcl, admin, etc.)

I don't have access to BPWS as I'm not a certified partner, just a hobbyist trying to restore this PBX for a home lab project.
I would really appreciate any help. Thank you in advance!