Me310g1ww DNS and signal qualty problems.

[cdprf]

We have multiple devices with varying firmware versions, primarily 224 and 226. Typically, the CSQ is around 25-30. However, since implementing firmware 226, we have encountered a problem with the CSQ dropping to 15-16.
When downgrading to firmware 224, the DNS command response is "UNKNOWN". Is there an alternative method to set DNS settings on firmware 224? Alternatively, with firmware 226, is there a command or option to increase the CSQ level?

Any assistance would be appreciated.