The previous upgrade on my Javelin from OS 188.8.131.521 Optus to OS 184.108.40.2061 Cosmote has disabled the keypad lock button and function. Since then I have tried to installed the same OS from Singtel and/or Telkomsel (the actual vendor of my Javelin as in the vendor id) and Indosat. However, I believe Cosmote has the best battery, performance, and memory management.
Recently, Wind Hellas has released he new OS 220.127.116.119. I have struggled to download the file but eventually succeeded. As usual the upgrade went smooth. Surprisingly, the new OS has restore the keypad lock function. Although the keypad lock icon is still missing, but the keypad button on top of Javelin has been working again. Instead of locking the keypad, the button now served as standby button. Just one press and Javelin will sleep.