C29S firmware trouble

I seemed to make a mistake during updating the firmware for my C29S.
Now it doesn't boot nor appear on the network.
(When power on, just the yellow LED go on and nothing happens.)

Please tell me how I can do for my C29S?
I heard the firmware can be recovered via SD card....

Dear customer ,
To upgrade the firmware, please give me the current firmware version of your camera, let's check if there is newer firmware, thanks!

Thank you, VStarcam Shop.

I think
Firmware:48.53.185.59
WebUI:JP185.23.53.21
(I cannot confirm these because C29S doesn't boot up.)

By the way. older version may be preferable for me.
I have to use C29S with Eye4 for PC in the isolated LAN network without internet connection.
But the method I used seems not to work with recent firmware.
My method:
   First, I launch Eye4 in the network with internet connection.
   Then, I move my PC to the isolated LAN without exiting Eye4 and connect C29S by Eye4.
This may not be recommended usage but I have to use C29S and Eye4 in the isolated network anyway.

Thank you.

hbadmin replied at 2022-7-4 15:52
Dear customer ,
To upgrade the firmware, please give me the current firmware version of your camera ...

Hi, VStarcam Shop,

Please give me the direction how to recover my C29S anyway.

Thank you.

Hi, VStarcam Shop,

Please give me the direction how to recover my C29S.
My C29S still doesn't work.

Thank you.