model B wrong amount of ram displayed

Question

I have model B with 512 MB of RAM, but htop displays

92/231MB

free -h

pi@raspberrypi ~ $ free -h
             total       used       free     shared    buffers     cached
Mem:          231M       214M        16M        11M        16M       105M
-/+ buffers/cache:        92M       139M
Swap:         481M         0B       481M

gpu_mem is set to 16M

I'm using wheezy image which is upgraded to jessie, but problem was also on wheezy. How to enable all 512 MB?

*Model B rev2, I know because of "Made in UK" and copyright date is 2011.12

pi@raspberrypi ~ $ cat /proc/cpuinfo
processor   : 0
model name  : ARMv6-compatible processor rev 7 (v6l)
Features    : swp half thumb fastmult vfp edsp java tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part    : 0xb76
CPU revision    : 7

Hardware    : BCM2708
Revision    : 1000004
Serial      : 0000000040b2d6e4

Answer 1

You can check how much RAM your Pi should have by checking the board revision.

The board revision can be found by examining the /proc/cpuinfo file on the Pi.

E.g. on my B+

$ cat /proc/cpuinfo
processor   : 0
model name  : ARMv6-compatible processor rev 7 (v6l)
Features    : swp half thumb fastmult vfp edsp java tls 
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part    : 0xb76
CPU revision    : 7

Hardware    : BCM2708
Revision    : 0010
Serial      : 00000000f7094d77

The board revision is 0010 (this is a hex number, so 16 decimal). The CPU revision is irrelevant.

http://elinux.org/RPi_HardwareHistory maintains a list gives details (including RAM fitted) for each known board revision.