Today a new fix for Metro Last Light for CFW 3.55 is readily available to download thanks to DUPLEX. Check out the release notes and the download link below.
1) Download the files using the link below
2) Launch MultiMAN and FTP into dev_Hdd0/Games/BLUS31184
3) Replace the EBOOT.bin inside of the USRDIR folder and the Param.sfo into of the BLUS31184
4) Disconnect FTP and Launch using MultiMAN