ZyXEL GS2200-48 Default ROM file

Hi,

I recently purchased a second-hand ZyXEL GS2200-48 and am unable to access it due to unknown credentials. I am hoping someone can share the default ROM file so I can reset it via console.

Here is what I have tried so far:

Switch details:

• Model: GS2200-48
• Bootbase Version: V1.0 | 06/18/2009
• ZyNOS Firmware: V3.80(BPR.2) | 6/9/2011
• MAC (mgmt): b0:b2:dc:2e:93:4c

What I have tried:

1. Serial console via USB-to-serial adapter (FTDI, COM5) — Connected using TeraTerm at 9600 baud, 8N1, no flow control. The switch boots fine and I can see all boot output. However after "Press ENTER to continue..." the CLI does not respond to any input. I can type and see characters but the switch does not respond to commands such as "admin", "1234", "show version", "sys reboot" etc. I also tried sending a break signal with no effect.
2. Debug mode — Attempted to press a key during the 3-second debug mode window at boot. Keypresses are occasionally registered (visible as characters in the dots) but the switch never drops into debug mode.
3. Hardware reset button — Held the reset button for 10, 15, 30 seconds both after boot and during power-on. The switch reboots but the boot output still shows "Restore System Configuration" indicating the reset is not taking effect.
4. Network access via MGMT port — Connected directly to the dedicated MGMT port with a static IP of 192.168.1.100/24. The port shows a link light but the switch does not respond to pings on 192.168.1.1 or any other address across both 192.168.1.x and 192.168.0.x subnets. Also tried DHCP — got a 169.254.x.x self-assigned address, confirming the switch has no DHCP server active.
5. ZyXEL download library — The GS2200-48 no longer appears in the ZyXEL download library so I cannot obtain the ROM file myself.

What I need:
The default ROM file for the GS2200-48 (firmware V3.80 BPR.2 or compatible) so I can upload it via XMODEM in TeraTerm once I get into debug mode, following the ATLC procedure.

I have seen Zyxel_Melen help others in identical situations (e.g. GS2200-24, GS1920-48HP threads) by providing the ROM file. Would really appreciate the same help here.

Thanks in advance!