While L1 has empty flash cell erased to zero, at least F1/F4 are erased to 0xff.
[fw/stlink] / gdbserver /
drwxr-xr-x   ..
-rw-r--r-- 242 Makefile
-rw-r--r-- 2684 gdb-remote.c
-rw-r--r-- 177 gdb-remote.h
-rw-r--r-- 25001 gdb-server.c