CRA notes that a s. 94 deemed-resident trust can access the general s. 164(6) carry-back rules

Although a non-resident estate cannot carry back, to the terminal return of the Canadian deceased, capital  losses realized by it on shares of a Canadian corporation which are not taxable  Canadian property, this is not a problem where the estate is deemed to be a resident trust under s. 94.  Furthermore, the estate can also carry back a capital loss realized on the deceased's principal residence, assuming that it was not personal use property to any beneficiary.

Neal Armstrong.  Summary of 12 February 2013 Memorandum 2012-0437211I7 F under s. 94(3)(a).