1M(512k SPIFFS) does not work, 1M(256k Spiffs) does

[Quaras]

Hey,
im currently trying to create my own Webserver which serves an Website, when I try to upload my HTML, JS and CSS files on the ESP8266 ESP-01 some files are left out when the Flash has the 1M(512k SPIFFS) configuration, everything works fine on 1M(256k Spiffs) tho.
Would very much like to use a 512k SPIFFS but cant.

Thanks
Quaras