Whew...finally found a solution on the forum for STAT.exe crashing! (I do feel all alone out here, though 
)
Bingo! No crash, no error, and I get an output that I don't quite understand:
text data bss dec hex filename
97592 832 10076 108500 1a7d4 ../build/target/main/platform-0-lto/Project.elf
The BIN file is 98,428 bytes. But if the "DEC" value is to believed, I'm just about out of memory (according to @mdma, 110,592 bytes max.) But DFU-Util downloads the 98,428 bytes of the BIN file, not the 108,500 of the "stat" output.
WiFi.ping() is just simply, plainly broken. I don't understand how, as the changes don't seem major. Serial.println(WiFi.ping(WiFi.gatewayIP())); returns zero. Every time. I have confirmed that the IP address is correct in "wlan_hal.c", where the inet_ping function is found...and even tried reversing the sequence of the IP address bytes (3210 -> 0123). The function uses netapp_ping_send (found in "netapp.c"), which has not changed at all.