Sounds like SafeA9LHInstaller bricked you. The blue light staying on without a SD card at that point usually means the exploit being used to fire up arm9loaderhax messed up. Otherwise your system would shut off when it can't find the file.
Sorry. It's rare, but it does happen even if you do everything right. This also happened to the first 2DS I tried, and a few others here. Should be able to be fixed via hardmod assuming you have backups. There might be another solution but I wasn't able to find it.
Double check all your files on the SD card etc to make sure you did everything correctly. If you find something wrong make some noise on the github page by filing an issue.
@Alex658 - SafeA9Installer was updated a couple months ago to no longer use bad otp.bin files. I think this is the same kind of brick that would happen if you did though, so it might not be perfect.