12297

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

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.

See Also

• ticket #12297,