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OLPC has begun enabling the second processor core in the XO-4 laptops.
Contents
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
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/bootfw.zip file, to prevent automatic firmware upgrade,
- downgrade the kernel,
- shutdown,
sudo poweroff
- downgrade the firmware,
ok flash u:\q7b43.rom
- allow the laptop to boot.
