How can i get planck_2018_transfer_out.dat with a Non-standard cosmological model？

[Yan jian]

I need to use the transfer function generated by CAMB to generate the initial conditions for the N-body simulation of my new dark matter model. This requires the planck_2018_transfer_out file. The new dark matter model adds a term T^2 (k) to the dark matter transfer function. I can modify the second column of the planck_2018_transfer_out file directly to get the transfer function of the new dark matter model. However, the change in the CDM transfer function will inevitably cause changes in the transfer functions of other substances (especially baryons). I can also simply do the same processing on the transfer functions of other columns, but this is definitely not rigorous.
My question is: How should the change in the cold dark matter transfer function be considered in the calculation of CAMB for other components?

[Antony Lewis]

You should implement a self-consistent modified perturbations/initial conditional model in CAMB.