How can I get my photos off of an old cell phone in Linux?

I have an old, non-Android flip phone (Samsung SPH-M400) from about 2012, and I would like to get the photos off of it. The phone is fully functional, but its service is deactivated. I have tried everything I can think of to get those photos off. The hard drive is not removable, so I can't take it out. The phone does have Bluetooth, but I don't think you can use it to share photos (I don't think the firmware allows it). I even took the phone to the Sprint store, and they tried several methods to get the photos off (e.g. connecting the phone to their software, and reactivating the phone to Sprint's network). All of these methods failed, mostly due to the fact that the phone is old and is not really supported anymore. However, I am thinking there must be a way to do this in Linux. If I connect the phone through USB to my Linux computer, it is recognized. However, it does not seem to be mountable in the way I'm familiar with (the lsblk and fdisk -l commands don't list anything related to my phone), so I can't access the hard drive. However, the lsusb command gives me the following entry for the phone: Bus 001 Device 005: ID 04e8:6640 Samsung Electronics Co., Ltd Usb Modem Enumerator Also, I see the following directories/files created after connecting the phone: /dev/serial /dev/ttyACM0 Is there a way I can access the photo files on my phone?