be cautious, some of these power supplies have an adjustment for the 5 volt as well as some have a 3.3 volt adjustment as well. (even if unused) make sure you aren't tweaking the wrong adjustment.
if you bought a replacement drive (say off ebay) they probably should have supplied one for you. (most listings for replacement drives i've seen also include the bootrom.
if you copied the old drive... your "new drive" is no better than your old drive and will have the same broken bits copied over.
the TL;DR on the bootrom is the old boot rom versions required a drive capable of telling the system it was the only harddrive. (the original drive did this... newer drives do not)
if your replacement drive is an older drive capable of being set as a "single" drive, (has single SP/master/slave/CS settings) you don't need to change the bootrom for a new one. the drive just needs to be configured as a single/master drive
if your replacement drive is a newer drive with only master/slave/CS settings, you need a newer version bootrom.
long version:
Each IDE/ATA channel can support either one or two devices. IDE/ATA devices each contain their own integrated controllers, and so in order to maintain order on the channel, it is necessary to have some way of differentiating between the two devices. This is done by giving each device a designation as either master or slave, and then having the controller address commands and data to either one or the other. The drive that is the target of the command responds to it, and the other one ignores the command, remaining silent.
Devices are designated as master or slave using jumpers, small connectors that fit over pairs of pins to program the drive through hardware. Each manufacturer uses a different combination of jumpers for specifying whether its drive is master or slave on the channel. As long as one drive is jumpered as master and the other as slave, any two IDE/ATA/ATAPI devices should work together on a single channel. Unfortunately, some older hard disks will fail to work properly when they are placed on a channel with another manufacturer's disk.
One of the reasons why drives don't always "play nicely together" has to do with the Drive Active / Signal Present (/DASP) signal. This is an IDE/ATA interface signal carried on pin #39, which is used for two functions: indicating that a drive is active (during operation), and also indicating that a slave drive is present on the channel (at startup). Some early drives and computers don't handle this signal properly (a residue of poor adherence to ATA standards many years ago).
When using only a single drive on a channel, Newer hard disks have only a jumper for master or slave; when the drive is being used solo on a channel it should be set to master. Other manufacturers, notably Western Digital, actually have three settings for their drives: master, slave, and single. The last setting is intended for use when the drive is alone on the channel. This type of disk should be set to single, and not master, when being used alone.
Newer computers fixed this issue with the IDE/ATA interface by simply timing out if there was no response from a slave drive. (or no connection)
So the issue arises that the Golden tee board waits for the signal from the drives to ensure they are ready to boot. in a nutshell the original hard drive says "yes i'm ready...I'm also the only drive...so don't bother waiting for any other drives" the game says okay and proceeds to boot... the newer drives say "yes i'm ready." then the computer waits for a response from a slave drive that never comes... thinks there is something wrong and reboots in an attempt to fix the issue, hoping to hear from the drive again after a reboot.
the latest eagle bootrom fixes this issue by forcing the boot process to continue with only one drive because there was only ever one drive to begin with.