Reverse engineering Yealink T41P firmware

Hi folks, not sure if this is the right place but so please lmk if there is a better place to put this:

I'm currently attempting to reverse engineer yealink t41p IP phone firmware since the device is out of support for some years and but works very well imo. For security reasons and keeping the devices out of the trash, I would like to provide open source firmware for it. I recently learned how the process with clean room reversing works but I'm stumbling at the first step already. Here is what I attempted so far:

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk --signature T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -E T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     ENTROPY
--------------------------------------------------------------------------------
16384         0x4000          Rising entropy edge (0.984980)
20480         0x5000          Falling entropy edge (0.783278)
32768         0x8000          Rising entropy edge (0.992664)
45056         0xB000          Falling entropy edge (0.601562)
65536         0x10000         Rising entropy edge (0.991434)
815104        0xC7000         Rising entropy edge (0.992069)
2945024       0x2CF000        Falling entropy edge (0.668870)
2949120       0x2D0000        Rising entropy edge (0.993514)
8155136       0x7C7000        Falling entropy edge (0.843171)

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -BE T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------


DECIMAL       HEXADECIMAL     ENTROPY
--------------------------------------------------------------------------------
16384         0x4000          Rising entropy edge (0.984980)
20480         0x5000          Falling entropy edge (0.783278)
32768         0x8000          Rising entropy edge (0.992664)
45056         0xB000          Falling entropy edge (0.601562)
65536         0x10000         Rising entropy edge (0.991434)
815104        0xC7000         Rising entropy edge (0.992069)
2945024       0x2CF000        Falling entropy edge (0.668870)
2949120       0x2D0000        Rising entropy edge (0.993514)
8155136       0x7C7000        Falling entropy edge (0.843171)

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -y T41-36.83.0.160.rom 
haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -e T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -I T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
12622         0x314E          BFF volume entry, AIXv3, file name: "iX2jÅ

haui@TowerPC:~/Downloads/t41p-firmware$ binw^C

haui@TowerPC:~/Downloads/t41p-firmware$ binwalk -G T41-36.83.0.160.rom 

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------