Did you try 4.70.70?
Software_File(Version_02.02.50) EPK (rename to starfish-dvb-secured-k3lp-drd4tv-609-02.02.50_nsu_V3_SECURED.epk)
Software_File(Version_02.12.50) EPK (rename to starfish-dvb-secured-k3lp-drd4tv-609-02.12.50_nsu_V3_SECURED.epk)
Software_File(Version_04.70.04).zip
Software_File(Version_04.70.45) EPK
Software_File(Version_04.70.55).zip
Software_File(Version_04.70.65).zip
Software_File(Version_04.70.70).zip
Software_File(Version_04.70.85) EPK
Software_File(Version_04.70.85)
Software_File(Version_04.80.72) EPK (rename to starfish-dvb-secured-k3lp-573.drto.k3lp-5731701-04.80.72-prodkey_nsu_V3_SECURED.epk)
Software_File(04.70.95) EPK (rename to starfish-dvb-secured-k3lp-573.drto.k3lp-57322-04.70.95-prodkey_nsu_V3_SECURED[0].epk)
Software_File(04.80.95) EPK (rename to starfish-dvb-secured-k3lp-573.drto.k3lp-57322-04.80.95-prodkey_nsu_V3_SECURED.epk)
Software_File(04.71.00) EPK (rename to starfish-dvb-secured-k3lp-573.drto.k3lp-57323-04.71.00-prodkey_nsu_V3_SECURED[0].epk)
Software_File(05.80.02) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61302-05.80.02-prodkey_nsu_V3_SECURED[1].epk)
Software_File(05.80.03) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61303-05.80.03-prodkey_nsu_V3_SECURED[0].epk)
Software_File(05.90.01) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61301-05.90.01-prodkey_nsu_V3_SECURED.epk)
Software_File(05.90.02) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61302-05.90.02-prodkey_nsu_V3_SECURED[0].epk)
Software_File(05.90.03) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61303-05.90.03-prodkey_nsu_V3_SECURED.epk)
Software_File(05.80.10)
Software_File(05.80.10) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61304-05.80.10-prodkey_nsu_V3_SECURED.epk)
Software_File(05.80.20) EPK (rename to starfish-dvb-secured-k3lp-613.dunggir.k3lp-61306-05.80.20-prodkey_nsu_V3_SECURED[1].epk)
P.S.
I see no difference between .45 and .55. So I think the slowdown is due to something else.
Probably is better if you reset to factory settings.
Note:
Version 4.80.72 is a downgrade to a verision similar to 04.70.70 of May 2018.
Note:
Version 4.80.95 and 4.70.95 are the same firmware.
Note:
04.71.00 Seems a good firmware (as it was 04.70.45).
Versions 5.80.XX and 5.90.XX are exactly the same firmware.
05.90.02 Seems also a good firmware.
Release History
[03.50.45]
1. Improve no signal or video broken after inserting CI CAM and DC Power Off/On.
[04.70.04]
For 2017 OLED TVs (W7, G7, E7, C7, B7)
1. Support TrueHD audio format through HDMI
2. Technicolor Expert mode
For 2017 Super UHD 4K TVs (SJ)
1. Technicolor Expert mode
For 2017 Ultra HD 4K TVs (UJ)
1. Add an Apply to all input feature in Color Management Setting
2. Improving HDD detection speed
3. Add function for maintaining compatibility of remote controller
[04.70.20]
1. Fix that CH reservation is deleted after smart retune.
[04.70.45]
1. Fix that video is greenish in HbbTV HDR contents
[04.70.55]
1. Apply the GDPR. (General Data Protection Regulation)
[04.70.85]
1. Fix the TV reboot issue due to unstable Wi-Fi connection
[04.71.00]
1. Fix that the scrambled channel is not shown due to CI+ key read failure
[05.80.10]
1. Improvement
1) To improve that the subtitle is not displayed when HbbTV app in on. (except US Model)
2) Change HDR luminance curve. (webOS4.0 O18 Model)