U-boot is not a BIOS (or firmware) as found on a PC, so it would be better described as a monitor. When the computer is powered on or reset, U-boot's job is to initialize the hardware and to start the booting process of the system you want (AmigaOS or Linux). It also enables you to define some settings that you may want to use either for the next boot or for every time you use your computer. There are two interface modes for U-boot; a console mode and a graphical mode. If you are not an expert don't panic, because once you have setup some U-boot variables, you'll use the console very rarely. Typically you will only use the graphic mode, i.e. the U-boot menus, which are much easier to use. Your computer can boot in many different ways, depending how you setup your U-boot variables. U-Boot can even be updated from the standard Amiga "Prefs" panel.
While U-Boot may not be the best solution for the next generation Amiga hardware, it still allows it to do a lot of things, and enhancing U-boot is not a priority for the OS4 team at this time because it has other more important things to do. When the time comes, U-boot will be updated or could even be replaced by a better solution. Until then it's more than capable for our needs. If necessary the chip can be replaced, and new facilities can be added as the technology evolves.
The U-Boot ROM is located near the rear of the board between J9 and J10 (PCI slots) as shown by the white arrow, and is rather
tricky to remove even with a ROM puller because the socket is very close to the PCI slots. Many of the early motherboards were
supplied with a version of the U-Boot code which did not support floppy drives, and these needed to be updated to a later
version. However, some of the earlybird machines supplied prior to June 2003 were supplied with a locked version of the ROM
which could not be updated, and this meant removing the ROM and returning it to the dealer and getting an unlocked replacement
ROM in exchange. Eyetech recommended using a bent paperclip rather than using a ROM puller, see the
article on IntuitionBase, but either way it requires
great care and dexterity. Once removed the ROM must be aligned so that the angled corner of the ROM chip is to the left rear
of the socket next to U16, and then it can be pushed firmly into the socket.
Later versions of the U-Boot ROM are unprotected but you will still need to set the U-Boot parameters to the correct values, and periodically you may have to update the U-Boot ROM as new images become available.
Disclaimer: Amiga Auckland have prepared the above information for the use of its members based on our experiences and as such is subject to revision at any time. Amiga Auckland cannot guarantee any of the information and cannot be held accountable for any issues that may result from using it.