I’ve tried the ChirpStack 4.11.x revision. It all looks right, except that the downlink freq for CN470 (LoRaMAC 1.0.4 RP002-1.0.3) is wrong. When Uplink FREQ is 470.9 for JoinRequest, the responsed JoinAccept is using Downlink FREQ=500.9MHz. According to RP002-1.0.3 CN470 Type-A 20MHz, the downlink FREQ is started from 483.9MHz. The correct downlink freq to answer the above JoinReques should use 484.5MHz. Is there anyway to change it through a configuration file?
It looks like CN470 changed between LoRaWAN 1.0.3 and 1.0.4+. If you are able to, you can make a patch and submit a Pull Request (PR).
Since CN470 was one of those fixed-channel regions, I don’t think you can do anything else other than making a change to this file and to build a new version of Chirpstack: lorawan/band/band_cn470_510.go at master · brocaar/lorawan
It would be ideal if there can be backward-compatibility with versions up to 1.0.3 and beyond 1.0.3, as seen in other bands like AU915: lorawan/band/band_au915_928.go at master · brocaar/lorawan
The cn470 plan implemented in chirpstack looks to be from rp 1.0.3a, where rx2 is 505.3 MHz
The new version is marked experimental in RP2 in all versions since it was introduced. It has not been confirmed to have been put in use.
The Rx2 frequency varies for 20Mhz, 26Mhz and A, B variations. This is by far the most difficult plan spec to implement.