Custom action during silent uninstall

Good day, everyone.

I need to remove specific file during silent uninstall (Installscript project).
Here's what I got:

1. Response file created with parameter (path to file marked for removal):

if(MODE=RECORDMODE) then
SilentWriteData( szAppKey, "svPath", DATA_STRING, svValue^svFile, 0 );
endif;

2. Silent mode looks like this:

function OnMaintUIBefore()

...

if(MODE=SILENTMODE) then
SilentReadData( szAppKey, "svPath", DATA_STRING, svPath, nvcount );
DeleteFile (svPath);
featureRemoveAll();

3. After which: Setup.exe /s /f1"path\to\.iss"

This does nothing - neither program nor file are removed. Is there any specific behavior I should consider when using custom actions in silentmode?
Also, is it possible to use silentmode without .iss file specified - like simply calling setup.exe /s to perform full silent uninstall?
Thank you.