12297: Difference between revisions
Jump to navigation
Jump to search
Line 48: | Line 48: | ||
* download the [http://dev.laptop.org/pub/firmware/q7b43/q7b43.rom q7b43.rom] old firmware, |
* download the [http://dev.laptop.org/pub/firmware/q7b43/q7b43.rom q7b43.rom] old firmware, |
||
* copy both to a USB drive, |
* copy both to a USB drive, |
||
* <font color="red">note</font>: remove the /bootpart/boot/ |
* <font color="red">note</font>: remove the /bootpart/boot/bootfw4.zip file, to prevent automatic firmware upgrade; |
||
rm /bootpart/boot/bootfw4.zip |
|||
* downgrade the kernel, |
|||
* downgrade the kernel, by forcing upgrade to lower version; |
|||
rpm --upgrade --force \ |
|||
kernel-3.5.7_xo4-20141118.2329.olpc.cd558cf.armv7hl.rpm |
|||
* shutdown, |
* shutdown, |
||
sudo poweroff |
sudo poweroff |
Revision as of 21:53, 14 January 2015
OLPC has begun enabling the second processor core in the XO-4 laptops.
Problem
The released operating systems 13.2.1 and 13.2.2 run only one core. The XO-4 underperforms compared to some other devices.
Solution
XO-4 only:
Upgrade to 14.1.0 once it is released
Workaround
Care is needed. Without the firmware upgrade, our dual-core kernel will not boot. With the firmware upgrade, the original kernel will not boot. The reason for the restriction is that changes to firmware and kernel must occur at the same time.
On unsecure laptops running 13.2.0, 13.2.1 and 13.2.2, upgrade the kernel and the firmware at the same time. The exact steps are:
- download the 3.5.7_xo4-20150108.2115.olpc.b2c8f99 kernel package,
- download the q7c02.rom new firmware,
- copy both to a USB drive,
- add battery and power cable, and wait for the laptop to finish charging,
- upgrade the kernel,
sudo rpm -U kernel-3.5.7_xo4-20150108.2115.olpc.b2c8f99.armv7hl.rpm
- shutdown,
sudo poweroff
- upgrade the firmware,
ok flash u:\q7c02.rom
- allow the laptop to boot.
Reverting
- download the 3.5.7_xo4-20141118.2329.olpc.cd558cf kernel package,
- download the q7b43.rom old firmware,
- copy both to a USB drive,
- downgrade the kernel,
- shutdown,
sudo poweroff
- downgrade the firmware,
ok flash u:\q7b43.rom
- allow the laptop to boot.
Using a single core kernel on 14.1.0
Certain tasks may benefit from the higher memory bandwidth of the single core kernel.
- download the 3.5.7_xo4-20141118.2329.olpc.cd558cf kernel package,
- download the q7b43.rom old firmware,
- copy both to a USB drive,
- note: remove the /bootpart/boot/bootfw4.zip file, to prevent automatic firmware upgrade;
rm /bootpart/boot/bootfw4.zip
- downgrade the kernel, by forcing upgrade to lower version;
rpm --upgrade --force \ kernel-3.5.7_xo4-20141118.2329.olpc.cd558cf.armv7hl.rpm
- shutdown,
sudo poweroff
- downgrade the firmware,
ok flash u:\q7b43.rom
- allow the laptop to boot.