Internal eUSB issue of the Juniper SRX 300 series
The Juniper SRX300 series represents the most affordable line of NGFW (Next-Generation Firewall) devices offered by Juniper Networks. Originally announced in 2016, these devices have been widely deployed to connect branch offices of various sizes to the Internet and to establish VPNs — including LAN-to-LAN and Remote Access configurations. Recently, there has been a noticeable increase in cases where SRX300 devices fail during operation or boot. In such scenarios, the system may hang and drop into the loader> or db> prompt, indicating a failure to complete the boot process. ⚠️ Problem Description All models in the SRX300 series — except for the SRX380 — are equipped with identical 8GB eUSB modules (personally verified on SRX300 and SRX340). Over time, the internal flash memory may degrade due to the limited number of write cycles. This degradation can prevent the device from booting properly, resulting in a fallb...