Download- Byhss Ly Tyz Mhjbt Msryt Fy Alatwbys... -

Let’s try on “ly” = “my” (l→m, y→z: “mz” no).

decodes (with shift -1) to: “Download- axgrr kx sya lgias lrqxh ex zksvaxr” — not readable. Download- byhss ly tyz mhjbt msryt fy alatwbys...

Shift each letter backward by 1: b→a, y→x, h→g, s→r, s→r → “axgrr” no. Shift backward by 3: b→y, y→v, h→e, s→p, s→p → “yvepp” no. Let’s try on “ly” = “my” (l→m, y→z:

(download the bus in Egypt) — playing on “Download- byhss…” being a clue to decode as “Download- al autobees fi masr” but with letters shifted. Shift backward by 3: b→y, y→v, h→e, s→p,

But if it’s a Caesar shift of -1 for whole phrase: b→a, y→x, h→g, s→r, s→r → “axgrr” — not matching.

If “alatwbys” original intended = “alautobees” → “alatwbys” shift +1: a→b, l→m, a→b, u→v, t→u, o→p, b→c, e→f, e→f, s→t → “bmbvupcfft” no.