[QUOTE=ninigirl;2078361]Sorry for my bad English I come from Germany.
[/QUOTE]
This happens here and there 
[QUOTE=ninigirl;2078361]
I wanted my DVD burner LG GSA H54L to GSA H55L flashing.
Do everything goes according to instructions, but the error message “Invalid F / W - Buyer mismatch” What can I do?
[/QUOTE]
In case you do not mind to loose your warranty…
Load the firmware H55L firmware with MCSE (read the instructions), save the stand alone flasher, continue to work with the unzipped firmware, select the H54L drive ID in the crossflash box in the lower right, check the ‘increase read speed’ checkbox if you like, save the patched firmware, flash it with the previously saved stand alone flasher.