xref: /aosp_15_r20/external/coreboot/Documentation/mainboard/asus/p3b-f.md (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c) 
1# ASUS P3B-F
2
3This page describes how to run coreboot on the ASUS P3B-F mainboard.
4
5## Flashing coreboot
6
7```{eval-rst}
8+---------------------+---------------------------+
9| Type                | Value                     |
10+=====================+===========================+
11| Model               | SST 39SF020A (or similar) |
12+---------------------+---------------------------+
13| Protocol            | Parallel                  |
14+---------------------+---------------------------+
15| Size                | 256 KiB                   |
16+---------------------+---------------------------+
17| Package             | DIP-32                    |
18+---------------------+---------------------------+
19| Socketed            | yes                       |
20+---------------------+---------------------------+
21| Write protection    | See below                 |
22+---------------------+---------------------------+
23| Internal flashing   | yes                       |
24+---------------------+---------------------------+
25```
26
27flashrom supports this mainboard since commit c7e9a6e15153684672bbadd1fc6baed8247ba0f6.
28If you are using older versions of flashrom, below has to be done (with ACPI disabled!)
29before flashrom can detect the flash chip:
30
31```bash
32  #  rmmod w83781d
33  #  modprobe i2c-dev
34  #  i2cset 0 0x48 0x80 0x80
35```
36
37Upon power up, flash chip is inaccessible until flashrom has been run once.
38Since flashrom does not support reversing board enabling steps,
39once it detects the flash chip, there will be no write protection until
40the next power cycle.
41
42### CPU microcode considerations
43
44By default, this board includes microcode updates for 5 families of Intel CPUs
45because of the wide variety of CPUs the board supports, directly or with an
46adapter. These take up a third of the total flash space leaving only 20kB free
47in the final cbfs image. It may be necessary to build a custom microcode update
48file by manually concatenating files in 3rdparty/intel-microcode/intel-ucode
49for only CPU models that the board will actually be run with.
50
51## Working
52
53- Slot 1 and Socket 370 CPUs and their L1/L2 caches
54- PS/2 keyboard with SeaBIOS (See [Known issues])
55- IDE hard drives
56- USB
57- PCI add-on cards
58- AGP graphics cards
59- Serial ports 1 and 2
60- Reboot
61
62## Known issues
63
64- PS/2 keyboard may not be usable until Linux has completely booted. With SeaBIOS
65  as payload, setting keyboard initialization timeout to 2500ms may help.
66
67- The coreboot+SeaBIOS combination boots so quickly some IDE hard drives are not
68  yet ready by the time SeaBIOS attempts to boot from them.
69
70- i440BX does not support 256Mbit RAM modules. If installed, coreboot
71  will attempt to initialize them at half their capacity anyway
72  whereas vendor firmware will not boot at all.
73
74- ECC memory can be used, but ECC support is still pending.
75
76## Untested
77
78- Floppy
79- Parallel port
80- EDO memory
81- ECC memory
82- Infrared
83- PC speaker
84
85## Not working
86
87- ACPI (Support is currently [under gerrit review](https://review.coreboot.org/c/coreboot/+/41098))
88
89## Technology
90
91```{eval-rst}
92+------------------+--------------------------------------------------+
93| Northbridge      | Intel I440BX                                     |
94+------------------+--------------------------------------------------+
95| Southbridge      | i82371eb                                         |
96+------------------+--------------------------------------------------+
97| CPU              | P6 family for Slot 1 and Socket 370              |
98|                  | (all models from model_63x to model_6bx)         |
99+------------------+--------------------------------------------------+
100| Super I/O        | winbond/w83977tf                                 |
101+------------------+--------------------------------------------------+
102```
103
104## Extra resources
105
106[flashrom]: https://flashrom.org/Flashrom
107