As suggested in one of the answers, it's because of the base address, I used rbasefind to find the base_address of the firmware, and edited it to find the address of the bootloader as there was only two strings plus 11 false string positives.
If you have SWD you should be able to get at least the device ID or determine the device family. For example, most Cortex-M devices have a pretty uniform memory map.
You can also probe memory reads (e.g. each 0x1000 bytes) to determine what addresses are valid.
There are several ways to show the different functions of a binary file in radare2.
Start by opening the binary file and analyze it.
$ r2 -A libdbm64.so
The simplest way to list the functions, is the afl command which stands for analysis function list. The command will list all the functions in the binary and print it with four columns: ...