Can't apply a rest pose when model has shapekeys/flexes

[ficool2]

Note: already posted on facepunch but I figured I'll post here as well as more people know stuff about shapekeys/flexes

I posed a ported model, which has flexes, as close as I could to a TF2 character, but the issue now is I can't set its rest/reference post to be this current pose.

Trying to Apply Pose as Rest Pose fails as the mesh doesn't update to the new pose.
https://files.facepunch.com/forum/upload/111014/5457fb06-1af2-4046-9e4f-859dce787677/image.png
Trying to apply the Armature modifier in an attempt to fix the above issue also fails due to this error:
https://files.facepunch.com/forum/upload/111014/91ec5e21-aae5-4589-aabc-070c177378e6/image.png

Is there any workaround I can do (such as a plugin)? I must keep the shapekeys, so deleting them is not an option. Seperating the head is also not an option as I have adjusted the head/spine bones.

[Reoxur]

Theres an addon that does this

https://cdn.discordapp.com/attachments/306423116245106690/540550339275915264/unknown.png

[Reoxur]

https://lollypopman.com/2016/08/09/addon-shapekey-helpers/

Here I think its this, I use it often

[ficool2]

Originally posted by Reoxur:

https://lollypopman.com/2016/08/09/addon-shapekey-helpers/

Here I think its this, I use it often

Thanks, I did find another plugin that did this though already, but this one seems to be better anyway

The one I used: https://github.com/przemir/ApplyModifierForObjectWithShapeKeys

[Reoxur]

Ah yea, same thing, just less features lol