and this one https://www.sdcard.org/downloads/pls/simplified_specs/part1_410.pdf) shows that ACMD23
must be preceeded with CMD55 command as any other ACMD commands.

Also, after the block reading wait loop must be inserted before writing the next block of data to
the sd card

From Dmitry Nikolaev via Jussi Kivilinna

drivers/serial: Report correct number of bytes free in serial buffer with FIONWRITE.  From Jussi Kivilinna.

SAMV71: Quick'n'dirty port of the SAMA5 SSC driver to the SAM7.  The IP is compatible but there are still some DMA- and Cache-related issues that need to be worked out.

ARMv7-M MPU.  Bad syntax will cause failure to write the correct value to the MPU_RASR register.  From Juha Niskanen

libc: stdio: Fix NULL pointer dereference in ungetc(). If 'stream' was NULL, 'stream->fs_oflags' was evaluated.  From Juha Niskanen