Pukguksong-4 and -5

The new "thick" solid-fuel missiles Pukguksong-4 and -5 GLBM
North Korean first silo-based missiles ?

2021, January 14 -- The same missile, but now with a longer shroud on top, was shown at the latest parade. It is called "Pukguksong-5ㅅ". An escort team is missing because the longer shroud is blocking the platform on the transporter. Another difference could also be that the PS-4 did not have a real second stage. The PS-5 is probably as well as the PS-4 a silo-based missile.

2020, October 10 -- At the parade on the 75th anniversary of the founding of the Workers Party, a Pukguksong-4 was shown. It is not identical to the PS-3 SLBM. The PS-4 has a larger diameter and the escort (Army) signals that it is a GLBM.

Analysis

With the conclusive assumption that it is the transporter that was already used with the PS-3 at the parade in 2017 (albeit now with a modified frame and an additional axle), the diameter of the PS-4 is 1.80 m to measure. The length would be 9.8 m. The twin-tires have the same diameter as before of 1.04 m, but with different profile.

It is doubt that this thing is a real missile. No separation mechanism can be seen at the shroud, only a flange. It is likely that a new solid-fuel motor in the guise of a missile was prepared for the parade.

Note: The missile is believed to be labeled "Pukguksong-4ㅅ",
featuring a Korean letter.
Is it a letter "S" in the Korean alphabet standing here for silo ?
The logo on the escort's uniforms is unmistakable.
The PS4 is probably a silo-based missile.