Updating SSD firmware in old Macbooks
If you have a CD drive, you can update the firmware of Samsung's Sold State Drives (SSD). Samsung provide bootable disk images to update an SSD drive installed within a Mac:


  Samsung SSD Firmware Updates for Mac Users
  
  Below you will find the latest firmware downloads for recent Samsung-branded SSDs. 
  ISO files may be used only via DOS using a bootable CD/DVD.
  
  … 840 EVO, 840 PRO, 840, 830 Series, and 470 Series …


The process is not friendly but it works. The disk image needs to be burnt to a CD, then you boot your Mac from the disc. The updating process takes seconds and is not complex.

The disc contains a cut down edition of Linux. The result is a text based interface:



I recently applied the 840 EVO update and while my update was not destructive, you must back-up first. The update process explicitly warns that it could wipe the drive.