eswyft/mmga
0
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

update readme

Browse Source
This commit is contained in:
Evgeny Zinoviev 2019-07-06 23:30:35 +03:00
parent 33bb9f3275
commit 787c542f5e
1 changed files with 5 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
README.md
View File

@ -15,7 +15,7 @@ As of time of writing, following models are supported in coreboot. Other models
# apt install bison build-essential curl flex git gnat libncurses5-dev m4 zlib1g-dev make libpci-dev libusb-1.0-0-dev
```
On other distros package names might differ. Be sure to install **gnat** prior to building coreboot toolchain.
#### Building flashrom
First of all, grab recent flashrom source tree and build it:
```
@ -77,7 +77,7 @@ PR2: Warning: 0x00692000-0x01ffffff is read-only.
```
Looks like a bug in Apple's firmware. Obviously it should always be read-only.
Anyway, that means that after cold boot **`fd` and `me` regions are writable**, and that gives us around 1.5M of writable space. Since we can rewrite FD, we can write a new FD with custom layout. So **the idea is to repartition the flash chip** and flash new bios to a writable space.
Anyway, that means that after cold boot **`fd` and `me` regions are writable**, and that gives us around 1.5M of writable space. Since we can rewrite FD, we can write a new FD with custom layout. So **the idea is to repartition the flash chip** and flash new bios to a writable space.
Let's write a new layout (I decided to use `0x00000-0xfffff` region for convenience):
```
@ -194,7 +194,9 @@ Flash it:
```
./mmga flash-stage2
```
If it's done and you again didn't see any errors, you have to **shutdown** the laptop again. DO NOT REBOOT, shut it down. It's even more important now: if you reboot, old FD will be used, the one that describes `bios` region as `0x21000-0xfffff`. And since you just flashed `bios` to `0x21000-0x7fffff`, this `0x21000-0xfffff` will most likely just contain `FF`s, so the laptop won't boot and will look like a brick. In that case you will need to press and hold power button for ~10 seconds to hard reset. To avoid all that, just do not reboot, shut it down.
This may take a while, please don't interrupt and let it finish.
If you again didn't see any errors after it's done, you have to **shutdown** the laptop again. DO NOT REBOOT, shut it down. It's even more important now: if you reboot, old FD will be used, the one that describes `bios` region as `0x21000-0xfffff`. And since you just flashed `bios` to `0x21000-0x7fffff`, this `0x21000-0xfffff` will most likely just contain `FF`s, so the laptop won't boot and will look like a brick. In that case you will need to press and hold power button for ~10 seconds to hard reset. To avoid all that, just do not reboot, shut it down.
## Misc