U-boot configuration for Debian upgrade
Before you can upgrade Debian from Debian 8 (jessie) to Debian 9 (stretch), you have to change a setting in the u-boot configuration. Unfortunately, the default settings no longer work with Debian 9. The new settings are compatible with Debian 8 (jessie) and Debian 9 (stretch), so I suggest you make the changes now.
If you have serial console access to the mv2120, you can run some commands in u-boot. Simply interrupt the boot process by pressing a key and type the following:
setenv loadAddr 0x0600000 setenv bootcmd 'bootext2 0,1:1,2 0x0600000 /boot/uImage /dev/sda /dev/sdb' saveenv
If you don't have a serial console, you can make the changes from within Debian. Run the following commands:
cat >/etc/fw_env.config <<EOF /dev/mtd0 0x00000 0x1000 0x20000 EOF fw_setenv loadAddr 0x0600000 fw_setenv bootcmd "bootext2 0,1:1,2 0x0600000 /boot/uImage /dev/sda /dev/sdb"
This creates a config file so the u-boot environment can be modified and
fw_setenv to update two boot variables.
Once you made the changes, upgrades to Debian 9 should work fine and you can also use the Debian installer if you want to perform a new installation.
Please note that Debian 9 is the last release to support the HP mv2120.