Yes. Actually, it turns out that the `size` command miscomputed the size of data due to some linker trickery that Hubris OS does.
```
$ size ../modem.elf 
   text	   data	    bss	    dec	    hex	filename
 167284	   2188	  54644	 224116	  36b74	../modem.elf
```
This makes my problem much less mysterious. The numbers still don't add up, but they are a lot closer.