Hello @zajdee,
I’m glad to hear that you upgraded from Turris OS 3.x series to 4.0.5 on your router. I hope that everything works well for you.
In Turris OS 4.0.5, which is based on OpenWrt 18.06. I can confirm that package kmod-jool is being missing for PowerPC. I am not sure why the package is not there. I see that for Turris Omnia router it is there [1]. But I have good news for you on this one. We are working on Turris OS 5.0, which is currently in HBT (Testing branch) and the kmod-jool [2] is there for PowerPC as well. This release is based on top of OpenWrt 19.07. There is not going to be any Turris OS 4.x release anymore as OpenWrt 18.06 has scheduled EoL next month and we need to move on.
[1] https://repo.turris.cz/hbs/omnia/packages/core/
[2] https://repo.turris.cz/hbt/turris1x/packages/core/