In The Etruscan Language: An Introduction, Revised Edition on page 103, we are told: "Another imperative, ending in -ti, -th, or -thi, and used for the second person, is also found in the text inscribed on the mummy[...]" An imperative is a command such as "Go!" or "Know thyself!" and the mummy in question is none other than the Zagreb mummy wrapped in linen which has been inked with text. The document is referred to as the Liber Linteus. Yet, it's already abundantly clear upon reading Massimo Pallottino's The Etruscans that this same ending, normally written as -θi using the Greek letter theta to indicate the aspirated "t", is an inessive postclitic translated as "in" or "within". Pallottino gives an example of this ending in use on page 218 with an unobjectionable example: Aleθnas Arnθ Larisal zilaθ Tarχnalθi amce "Arnth Alethna (son) of Laris was a zilath in Tarquinia" (from the inscription TLE 174).
So we should be asking ourselves this question: WHAT examples of this supposed imperative are found in the Liber Linteus mummy text? Of course, the Bonfantes make little effort to justify any of their assertions on the language, save a few of their suspect examples like raχθ tura (claimed to mean "Prepare the incense!"), which are nothing more than ad hoc translations ripped from their proper context. This thereby leads us astute readers down another wild goose chase. I will spare some of you the trouble by listing out all the words with the ending -θi or -ti in the Liber Linteus that could possibly show an "imperative" as the Bonfantes claim:
haθrθi (LL 2.iv, 2.xvi, 5.v, 5.xii), repinθi-c (LL 2.iv, 2.xvi, 5.v, 5.xii), raχti (LL 2.v), crapśti (LL 3.xix, 4.viii, 4.xv, 4.xix, 6.xii), laeti (LL 6.v), θaclθi (LL 3.xx), θeiviti (LL 5.xx), faviti-c (LL 5.xxi), hamφeθi (LL 6.v), luθti (LL 6.xviii), celθi-m (LL 6.xviii), cilθcveti (LL 7.xiv), caiti-m (LL 8.x), ramurθi (LL 8.xiii), reuχzineti (LL 8.xiv), zamθi-c (LL 8.xvi), lauχumneti (LL 9.xxxiii), mutti (LL 10.ix), hausti (LL 10.xxiii), napti (LL 10.xxxiii), useti (LL 11.ix), catneti (LL 11.ix), lanti (LL 11.xxxi), eterti-c (LL 12.iii, 12.viii), unialti (LL 12.x), and etrinθi (LL 12.v)The list may seem daunting but it's easy to thin this herd down to a manageable size. For one thing, haθrθi and repinθi-c are pairs and immediately dismissable since they are shown with different declensional endings elsewhere in the same text (hante-c repine-c in the simple locative). The ending -c means "and" and can be used on both nouns to mean "both ... and ...". These are assuredly nouns, not verbs. In likewise fashion, θeiviti and faviti-c are paired and so they can be ruled out for the same reason just as easily. Should this all seem obscure to most, the example of unialti "in the temple of Uni" based on the name of the goddess Uni, is a clear example showing that -ti and -θi are indeed allomorphs both signifying "in", just as in the example of TLE 174. It's safe to say that luθti is yet another noun considering its inanimate plural, luθcva, attested in TLE 131 on Laris Pulena's sarcophagus. Whether one links the word celθi-m with added phrasal conjunctive -m to Celi , an Etruscan month name believed to correlate to our September, or to a noun celu "earth", regardless a verb this is not. While mutti may appear at first to have a shred of hope of being linked to the verb mut, the preceding locative-inclined demonstrative tei "at/in that" that modifies this word destroys that faith, showing us yet another noun. Surely, cilθcveti is a noun, an inanimate plural noun in fact, whose unmarked singular cilθ is easily retrievable just a few lines up at LL 7.vii and repeated at 12.xi, should we miss it the first time. Given hamφeś with another case ending at LL 6.iii, there's no question that hamφeθi only a couple lines down is also not a verb. Don't bet on useti either, since this is specifying "in the evening", a derivative of *us "setting (as of the sun, moon or stars)" which is found in the simple locative usi in LL 3.xix and 8.xv, and a morphological cousin of usilane elsewhere in the document which is paired with θesane "at dawn". I suppose one could waste one's time trying to force useti into an imperative to suit one's premature notions but it won't be a productive pursuit given the overwhelming evidence against it. It would be a waste of time explaining away most of the remaining words since there are no attested verbs to account for them anyways and so claiming that these are imperatives is childish fancy: crapśti, laeti, θaclθi, caiti-m, ramurθi, reuχzineti (LL 8.xiii: reuχzina), lauχumneti, napti, catneti (LL 10.xvi: caθnal), lanti, caiti-m, hausti, and etrinθi.
Only eterti-c could possibly be a verb form at all, and only if a link to eθar can somehow be established by its context. However even if it is based on a verb root, it still cannot be ruled out that it's not a declinable verbal noun as us "setting, dusk" apparently is. So yet again, the Bonfantes have no clear, tangible proof to back up their published claims.
So what about the example of raχθ tura supposedly meaning "Prepare incense!"? This phrase is attested at LL 2.xix and it's clear from a professional examination of this entire linen text and by taking into account what we can be sure of the Etruscan language that tura is a derivative of tur "to give", hence it can't reasonably be proven to mean "incense" but it no doubt refers to an "offering" or "gift" based on the self-evident etymology of the word. The translation of "incense" is a concocted fantasy lacking any methodological foundation. Now, interestingly, the first word claimed to be an imperative verb is attested several times in various forms, but only within the mummy text for the most part: raχ [LL 5.xvi, 6.xviii, 8.x], raχś [LL 5.xviii], raχti [LL 2.v], raχuθ [TCap xxxiv] and raχθ [LL 2.xix, 4.ix, 4.x, 4.xiii, 4.xxi, 5.vii, 5.viii, 5.xv, 9.vi, 9.xiii, 9.xv, 9.xvi]. While raχθ or raχuθ may look like a verb form, raχś seems to be on the other hand an example of a genitive case, implying a noun. It's hardly secure what this term really means in fact since much of the text is repetitive. A nebulous word like this is one of the poorest examples one could give to justify an imperative form in Etruscan but it seems that it all rests on this one case.
It's reasonable to reject the claim altogether on the miserable amount of evidence alone but it becomes all the more hokey when one realizes that the very source of this claim is in fact based on a careless assumption of yesteryear that Etruscan was an Indo-European language and that this ending must somehow relate to the Proto-Indo-European imperative ending *-dʰi . Clearly this claim is busted on numerous grounds.
 As an example, read Transactions of the Philological Society on page 51 as it was published in 1854 by the Philological Society in Great Britain: "As it is very likely that the Etruscan is one of the Indogerman family, the mi of that language is probably the oldest instance of the M usurping the nominative in an Indogerman language.". The antiquated belief that Etruscan is an Indo-European language, while already proven to be false many times in more ways than one, persists in the works of Zacharie Mayani and Massimo Pittau to this day. While a remote relationship with Etruscan and Indo-European is possible, the method of subjectively "eyeballing" similarities between languages to tease a translation out of them is simply not acceptable in modernday comparative linguistics.