Not a direct answer to your question, but maybe this is a solution for you.

M-x install-package shell-pop

To install the package shell-pop from melpa or melpa-stable. Then evaluate (for tryout in *scratch* via C-x C-e, later in your .emacs)

(global-set-key (kbd "<C-M-return>") 'shell-pop)

This pops up a shell in the lower part of your frame, in this case when pressing ctrl-meta-ret. Repeating the keyboard sequence returns back where you were.

Not a direct answer to your question, but maybe this is a solution for you.

M-x install-package shell-pop

To install the package shell-pop from melpa or melpa-stable. Then evaluate (for tryout in *scratch* via C-x C-e, later in your .emacs)

(global-set-key (kbd "<C-M-return>") 'shell-pop)

This pops up a shell in the lower part of your frame, in this case when pressing ctrl-meta-ret. Repeating the keyboard sequence returns back where you were.

See https://github.com/kyagi/shell-pop-el for details.