I do not have the new V2 device, remind you all, be careful.
The V2 seems still printed the model no R4A, but the WiFi shows MiWiFi-R4AV2.
Both hw / sw changed a little, details, please refer to
2023-05-30 update: now, openwrt snapshot version already support this device.
Topic for this device: Support for Xiaomi Router AC1200 (RB02)
SSH activate: https://4pda.to/forum/index.php?showtopic=988197&view=findpost&p=117646422 (not tested)
Thanks, RB02 / R4AV2 shares the same hardware? Need the V2 owners teardown and compare on both.
When V2 wifi connected to a master router, I got the "MiWiFi-R4AV2" in Status page of the master router .
Another V2 feature is the factory firmwae shows the version no is 2.30.20 (or later?), V1 is 2.28.xx.
you mean as host name for the DHCP lease ?
Yes, the host name.
The above RB02 (Xiaomi AC1200), also uses v2.30.20 firmware.
ok, updated.
The factory firmwae version number 2.30.20 is also important and significant.
V2 uses 2.30.20 only, cannot downgrade to 2.28.xx. and V1 cannot upgrade to 2.30.20.
Put that in plain English, I'm not familiar with the Xiaomi device(s) ... 
I mean to confirm a R4A router is V2, using the firmware number 2.30.20 should be easy than checking the host name for the DHCP lease.
updated warning,
thnx
i bought this device last week in china, the packaging box says "r4a", but once plug in my router, device name is "r4av2". tried OpenWRTInvasion but ssh not work. i returned it just now.
any other device recommend？
For such low-end router, many choices, get a second hand device if you donot care.
hello! I managed to get telnet access to R4AV2 without a chip programmer (it lacks dropbear in the firmware)
Here's a link to my GitHub comment: https://github.com/acecilia/OpenWRTInvasion/issues/141#issuecomment-1296033775
There is no automated script to install, just the technical details. But it should be easy to wrap it in a script.
It is reported that RB02 firmware is supported by R4AV2 (everything works except the LEDs)
I used the 4pda thread as a reference. It was not working initially, but I adjusted it so that it works. Thank you.
before buying from outside the box how to check if it's v2?
same questions, has you found any method,? how to check v2 or openwrt supported mi4a router.
There is no method to check from outside the box. I just checked the manufacture date if its old then its older version
