But, does operate normally, and boots normally. The current, installed, Crucial 240g SSD is built properly and will start properly if used with a USB to Sata drive cable, and using the boot menu (option key at startup) to select the drive as the efi (boot) device. I've tried 3 different drives, all of these brands (Kingston, Crucial, Adata) have all worked, in the past, with 2009 models, including this C2D 1286, without issue. The connector is in perfect condition, and the cable “snaps" onto the connector without any obstruction or unnecessary force. I have used a cotton swab and 91% IP to thoroughly clean the connector to eliminate any issues from a faulty connector, or debris blocking a contact. I've never experienced intermittent drive connector errors from a logic board. A Logic Board connector, in my experience, is either working or has failed. Unlikely, or the rotational drive would not be seen, or enabled. Bad or damaged SATA system board connector.Unlikely, due to rotational drive working perfectly I have read on these forums, and others, that this can be problematic with improperly shielded drive cables. I also lined the bottom of the chassis with insulated electrical tape to shield the cable. It establishes communications for a split second, then drops off, and repeats without booting. I.E., a bad/damaged/shorted drive cable, This would also explain the Slash-0/Apple Logo flashing. Intermittent communications with the bootable ssd device.Damaged or missing firmware that supports booting from an SSD device.(Not flashing folder, which indicates no usable system at all, or device found) NO APPROVED EFI version found supporting this system year/cinfiguration. Which of these do you believe is causing a MacBook Pro, mid-2009, C2D at 2.53ghz, 4g ram, 240g ssd from booting from any SSD device, and showing the “prohibitive" circle with slash icon. But, I need assistance on firmware, and advice of all types, please. This is what is leading me to believe that it must be one of these issues. It starts fine with any rotational drive, with efi signature, completing the exact same build procedures, used with an SSD build. Another fact, that I may have not mentioned. My current situation, after doing everything that should enable any system drive with efi, to successfully start this MacBook pro. Sometimes, it's the simple things we miss, like changing the selection for the startup drive in system preferences (which I have done). I am more likely to add ideas to help others. I'm not in this for profit, and I rarely post for help on here. I also assist our underpaid and overworked teachers to afford a totally refurbished MacBook Pro, at my cost for parts.
SAMSUNG SSD FOR MACBOOK PRO MID 2009 MAC
I try to help keep e-waste to a minimum, and assist low-income Mac users afford an older MacBook Pro, that is still worthy of use with modifications developed to the OS by smarter people than me. I have done everything a tech, of 22 years, can do on this one.