Did you read product Release Notes?
I don't think that Czech preboot is fixed.
I don´t know exactly what do you think.
Pre-Boot environment we use in Czech, German and English language with Czech, German and English keyboard Support.
There isn´t any language problem. I attach the picture what I mean (from CZ OS from EE for PC client)
Maybe you think very funny message (bad czech translate) before restarting (after install EEforPC client).
Once McAfee bought SafeBoot and renamed it the McAfee Endpoint Encryption should also fix the names of those products. (second picture) :-)
In PreBoot we have another problem. :-)
When we Enable in General-Miscellaneus- "Always enable pre-boot USB support (auto otherwise)" so NTB DELL Precision M4500 is frozen in preboot.
When we Disable this check box M4500 will be started but all of NTB´s (DELL D630, E6400 ...) will be problem with NumLock LED on USB keyboard. (still glow).
Many users use closed NTB with ext. LCD and keyboard.
NTB M4500 have new Bios (default setting) with SATA operation set to ATA mode.
There are many places in EEPC that SafeBoot word is used. That's a legacy that will never go away... I guess.
As for other problem, please check KB article on USB handback workaround, available since 5.2.4 (or even 5.2.3), but automated for some BIOS vendors in EEPC 5.2.5. Maybe you still need manual setup via USB.ini.
Please post separate issues in separate threads. That is better for everyone.