bcm53xx: use iflag=skip_bytes for dd command during sysupgrade
authorRafał Miłecki <rafal@milecki.pl>
Sat, 23 Dec 2017 22:14:25 +0000 (23:14 +0100)
committerRafał Miłecki <rafal@milecki.pl>
Fri, 29 Dec 2017 22:18:45 +0000 (23:18 +0100)
Since BusyBox 1.25.0 dd command supports iflag=skip_bytes which allows
skipping requested amount of bytes without reducing blocksize. Thanks to
this we can leave default blocksize and let dd work more efficiently.

On Netgear R6250 "dd skip=58 iflag=skip_bytes" can be 5 times faster
than "dd bs=58 skip=1" when extracting TRX out of CHK.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
target/linux/bcm53xx/base-files/lib/upgrade/platform.sh

index 1a33e3a..06451f1 100644 (file)
@@ -274,11 +274,11 @@ platform_pre_upgrade() {
 platform_trx_from_chk_cmd() {
        local header_len=$((0x$(get_magic_long_at "$1" 4)))
 
-       echo -n dd bs=$header_len skip=1
+       echo -n dd skip=$header_len iflag=skip_bytes
 }
 
 platform_trx_from_cybertan_cmd() {
-       echo -n dd bs=32 skip=1
+       echo -n dd skip=32 iflag=skip_bytes
 }
 
 platform_img_from_safeloader() {