… in a loop. Cisco warns Nexus 3000 upgrade could get you stuck ...
It's late 2016 and a USB stick can make a hash of MD5
Cisco has popped out a curious Field Notice warning owners of Nexus 3000 devices to be careful when they upgrade the devices' operating software, lest they enter a boot loop.
“Nexus 3000 Series platforms that run Release 6.0(2)U6(x) show an MD5 mismatch when you upgrade to Release 7.0x or later,” Cisco warns. “As a result, the switch will be in a boot loop.”
Stranger still, the problem's source seems to be a USB memory stick, albeit the specialised ones that Cisco uses as boot flash for Nexus devices.
As the Field Notice explains, “Some Nexus 3000 Series platforms listed in the Products Affected section that use 2G and 4G eUSB flash are greater than 48 sector/track disk geometry. The impacted images do not understand greater than 48 sector/disk geometry and thus an upgrade to any of these images throws an MD5 mismatch error.”
Switchzilla is working on a fix, which will land in any new version of the 7.0 branch of the Nexii's software. Until then, would-be-upgraders need to update their devices' BIOS before attempting an upgrade. ®