Poor wifi with Custom Roms

[nitram686]

Hi guys,
i'm trying to reanimate mi Desire HD. Researches at this forum did not help, so i hope you can help me.
I have got some problems with my wifi signal when using custom roms. when i use this rom

http://forum.xda-developers.com/showthread.php?t=840040

it works perfect. but at this rom i cant install fresh apps. so i think it could be a kernel issue.
a half year ago i installed the latest radio, version 26.17.14.11 but it didnt work for fixing the wifi problem.
i dont think, that the battery cover will be the problem, because wifi works perfect with the Revolution ROM.

has anybody an idea how i can fix that problem? or any links?

thanks for your help
greetings
Martin