Yes, you’re in luck! We added this internally for 0.4.6 - public announcement pending CLI support, which will make it easier to manage the DNS redirect entries.
If you want to go the manual route, here’s the format:
DNS redirect entries are stored in a 128 byte block at location 1890 in the DCT region.
The domain format is zero or more blocks like this:
[length of name (as binary)
e.g. “www.particle.io” is encoded as 17 bytes:
0x03 “www” 0x08 “particle” 0x02 “io” 0x00
The end of the list is denoted by an extra null byte (0x00).
Here’s an example with 2 FQDNs:
0x03 "www" 0x08 "particle" 0x02 "io" 0x00
0x05 "setup" 0x08 "particle" 0x03 "com" 0x00
To write a block like this to the DCT region, it’s simplest to first build the file, and then use DFU util to transfer:
echo -e -n "/x03www/x08particle/x02io/x00/x00" > dns_redirect
dfu-util -d 2b04:d006 -a 1 -s 1890 -D dns_redirect
The device does already recognise some DNSs that were added by broadcom, e.g. google.com.
I hope that helps!