k->n
c->o
d->k?
s->v?
w->r?

One-letter words
70.0      A
30.0      I

Two-letter words
20.5      co -> OF
11.4      Tc -> TO?
9.1       WE
9.1       Ia
6.8       ac -> _O
6.8       Ik -> IN|IS|IF -> IN?
6.8       Io
4.5       IT
4.5       vE
4.5       ng

Three-letter words
31.5      THE
18.5      gcj
9.3       Auu
9.3       Akt -> AN_|AS_|AF_ -> AND
6.5       fAk
5.6       AwE
2.8       cWk -> OWN|OWS|OWF -> OWN
2.8       HAa
1.9       ocw -> _OR
1.9       fwg
Seems to confirm k -> N and c -> O

Four-letter words
8.8       WITH
5.9       dkcW -> _NOW -> KNOW?
5.9       WIkt -> WIND?
4.4       fcnE
2.9       Wcuo
2.9       kEEt -> NEED?
2.9       fcwk -> _ORK
2.9       aIkz
2.9       tckT -> _ONT
2.9       THAT

Five-letter words
14.6      kEsEw -> NEVER
9.8       gcjuu
9.8       THIkd -> THINK
9.8       EAwTH -> EARTH
9.8       lAIkT
4.9       aTIuu
2.4       uEAwk
2.4       gcjsE
2.4       EsEwg -> EVER
2.4       jkTIu
Ever and never are consistent.

Single letter frequency
12.3      E      (given as 12.7)
9.8       c -> O (given as 7.5)
9.0       T      (given as 9.1)
8.4       k -> N (given as 6.7)
7.2       A      (given as 8.2)
7.1       H      (given as 6.1)
5.9       w
5.8       I
5.1       u
4.1       a
3.5       W
3.5       j
3.2       f
2.8       g
2.8       t
1.7       o
1.5       n
1.4       l
1.3       d
1.3       s
This makes the claim c -> O and k -> N seem dubious.
The all of the decoding in the second pass is based on this claim.