The stem of the second aorist passive is formed by adding -η- (or -ε-) directly to the verb-stem. Thus, ἐβλάβην
a. -η- appears in the indicative, imperative (except the third plural), and infinitive; -ε- appears in the other moods. -η- is found before a single consonant, -ε- before two consonants or a vowel except in the nom. neut. of the participle.590aD
For -ησαν we generally find -εν (from -ηντ, cross40) in Hom.; also in Doric.591
The second aorist passive agrees in form with the second aorist active of μι-verbs; cp. intransitive ἐχάρην
Primitive verbs showing in their stems the grades ε: ο: α have α. Thus an ε of a monosyllabic verb-stem becomes α, as in πλέκ-ω
Primitive verbs showing in their stems a variation between a short and long vowel have, in the second aorist passive, the short vowel. Thus τήκω (τακ-, τηκ-)
a. But πλήττω (πλαγ-, πληγ-)
The second aorist passive is the only aorist passive formed in Attic prose by ἄγνυ_μι (ἐά_γην), γράφω (ἐγράφην), δέρω (ἐδάρην), θάπτω (ἐτάφην), κόπτω (ἐκόπην), μαίνω (ἐμάνην), πνί_γω (ἐπνιγην), ῥάπτω (ἐρράφην), ῥέω (ἐρρύην active), ῥήγνυ_μι (ἐρράγην), σήπω (ἐσάπην), σκάπτω (ἐσκάφην), σπείρω (ἐσπάρην), στέλλω (ἐστάλην), σφάζω or σφάττω (ἐσφάγην), σφάλλω (ἐσφάλην), τύ_φω (ἐτύφην), φθείρω (ἐφθάρην pass. and intr.), φύ_ω (in subj. φυῶ), χαίρω (ἐχάρην active).
Both the first aorist passive and the second aorist passive are formed by ἀλείφω (ἠλείφθην), ἀλλάττω (-ηλλάχθην, ἠλλάγην), βάπτω (ἐβάφην), βλάπτω (ἐβλάφθην, ἐβλάβην), βρέχω (ἐβρέχθην), ζεύγνυ_μι (ἐζύγην), θλί_βω (ἐθλί_φθην), κλέπτω (ἐκλάπην), κλί_νω (-εκλίνην), κρύπτω (ἐκρύφθην), λέγω
Only those verbs which have no second aorist active show the second aorist passive; except τρέπω, which has all the aorists: active ἔτρεψα and ἔτραπον
The stem of the second future passive is formed by adding -ς όε- to the stem of the second aorist passive. It ends in -ησομαι. Thus, βληβήσομαι
κόπ-τ-ω, ἐκόπην κοπήσομαι; γράφω, ἐγράφην γραφήσομαι; φαίνω, ἐφάνην
Hom. has only δαήσεαι (ἐδάην
Most of the verbs in 594, 595 form second futures passive except ἄγνυ_μι, ἀλείφω, βάπτω, βρέχω, ζεύγνυ_μι, θλί_βω, κλέπτω, μαίνω, μάττω, ῥάπτω. But many of the second futures appear only in poetry or in late Greek, and some are found only in composition.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].