Computers/A20-OLinuXino-LIME2 (eMMC)
Contents
1 Device information
This computer continues to be produced over the years. Because of that it's normal to have small to medium variations of the device over time to continue to be able to produce it.
While tiny variations are probably not a noticeable, at some point the chip used for the Ethernet changed two times (probably because the older one was not available anymore).
The differences and support for it in Parabola were summarized in the table below:
| Revisions | Chip | Supported |
|---|---|---|
| A to E | Realtek RTL8211CL | Probably works |
| F to G2 | Realtek RTL8211E PHY | Yes |
| H to L | Micrel KSZ9031 PHY | Work in progress: A special u-boot that is needed to make Ethernet work is available outside of Parabola in the meantime. |
2 Other resources
There is a wiki page on the Lime2 and Lime2 eMMC on the linux-sunxi.org wiki.
3 Upstream status
For the supported versions:
| Software | Status |
|---|---|
| Linux | (Almost) complete support in Linux. |
| u-boot (bootloader) | (Almost) complete support in u-boot. |
The easiest way to Interact with that computer is to connect an HDMI display and an USB keyboard. This way it will be pretty similar to x86 laptops or desktop computers.
If you need to debug boot issues, you might also find it convenient to setup the UART.
For more details on how to setup the UART, see the the Adding a serial port section on the lime2 page on the linux-sunxi wiki.
Here's more details below on what user input / output peripheral work out of the box or not:
| Display | USB Keyboard | UART | USB OTG | Ethernet | |
|---|---|---|---|---|---|
| Bootrom | Unsupported | Unsupported | ? | FEL mode only under certain circumstances | ? |
| U-boot (bootloader) | HDMI displays work out of the box | USB Keyboards work out of the box | Settings: 1152008N1 (from u-boot environment) | Works but needs configuration | ? |
| Linux |
|
Works out of the box in Linux consoles | Settings: 1152008N1 (from /boot/extlinux/extlinux.conf) | Works but needs configuration | Works but needs usual user configuration |
| Systemd | N/A | Settings: 1152008N1 (from /boot/extlinux/extlinux.conf) | Works but needs configuration | Works but needs usual user configuration | |
| OpenRC | N/A | TODO: Test it | TODO: Test it | TODO: Test it | |
| Xorg | Work out of the box (tested with xfce4 and lightdm-gtk-greeter) | N/A | |||
| Wayland | Work out of the box (tested with weston and lightdm-gtk-greeter) | N/A | |||
If something doesn't work as intended it may be because of some bugs which needs to be fixed.
4 Booting
The bootloader cannot be installed on all storage devices, as the bootrom only supports loading it from certain storage devices.
See the table below to see which storage devices you can install the booloader on:
| Storage device | Bootloader can be installed |
|---|---|
| MicroSD | Yes |
| eMMC | Yes |
| SATA | No |
| USB keys, USB Hard drive, etc | No |
Once the bootloader runs, it can access files on USB keys, SATA HDD / SSD, etc.
However ARM bootloaders like u-boot often lags behind Linux:
- u-boot doesn't support all the newer ext4 filesystem features
- u-boot cannot open encrypted partitions
The installation instructions already takes all that into account, so you will either need to format the ext4 filesystem in a special way or convert it to not use certain features.
5 Installation
Available bootloaders:
6 Free software status
- The nonfree software present on the board is the eMMC firmware which is inside the eMMC. Note that most storage devices (HDD, SSD, MicroSD, eMMC, USB keys, etc) have a firmware inside.
- The board could probably meet the RYF requirements pretty easily as as far as I know everything works with free software (including the GPU and the video decoding offload). Note that certain software configurations might be needed to use the GPU such as Wayland or configuring randr render offload in Xorg.
