It appears the JUNOS image is missing. I have downloaded another JUNOS image from a healthy SRX240. However, I cannot figure out how to boot from USB and save the new JUNOS image from the mode I am in "=>"
I am assuming you already try the "reset" or "boot" commands and you reached the same prompt; if not please try them.
If the SRX is getting stuck on uboot (not even reaching Loader) you could try the steps mentioned in the following KB in order to upgrade/reinstall the Loader and maybe after that you could try to recover the device with a USB drive from the Loader:
I am getting this error "## No elf image at address 0x00100000"
I am currently in the => mode. The following commands I have access too:
askenv - get environment variables from stdin autoscr - run script from memory base - print or set address offset bdinfo - print Board Info structure boot - boot default, i.e., run 'bootcmd' bootd - boot default, i.e., run 'bootcmd' bootelf - Boot from an ELF image in memory bootloader - upgrade u-boot bootloader - upgrade loader bootloader - upgrade ushell bootloader - check u-boot bootloader - check loader bootm - boot application image from memory bootoct - Boot from an Octeon Executive ELF image in memory bootoctelf - Boot a generic ELF image in memory. NOTE: This command does not support simple executive applications, use bootoct for those. bootoctlinux - Boot from a linux ELF image in memory bootp - boot image via network using BootP/TFTP protocol bootvx - Boot vxWorks from an ELF image cmp - memory compare coninfo - print console devices and information cp - memory copy cpld - peek/poke CPLD crc32 - checksum calculation dhcp - invoke DHCP client to obtain IP/boot params dumpoct - dump octeon regs dumpstats - dump cavium stats echo - echo args to console eeprom - EEPROM sub-system erase - erase FLASH memory fatinfo - print information about filesystem fatload - load binary file from a dos filesystem fatls - list files in a directory (default /) flinfo - print FLASH memory information go - start application at address 'addr' gpio - read/write on gpio pins help - print online help i2c - read/write on i2c bus id_eeprom - peek/poke EEPROM ide - IDE sub-system iminfo - print header information for application image imls - list all images found in flash itest - return true/false on integer compare loadb - load binary file over serial line (kermit mode) loads - load S-Record file over serial line loady - load binary file over serial line (ymodem mode) loop - infinite loop on address range ls609x_read_reg - Read 88E6097 register md - memory display mdkinit - start MDK mm - memory modify (auto-incrementing) mtest - simple RAM test mw - memory write (fill) nfs - boot image via network using NFS protocol nm - memory modify (constant address) pci - list and access PCI Configuration Space pciemd - pcie memory display pciemw - pcie memory write pciereset - do PCIE reset ping - send ICMP ECHO_REQUEST to network host printenv- print environment variables protect - enable or disable FLASH write protection rarpboot- boot image via network using RARP/TFTP protocol read64 - read 64 bit word from 64 bit address read64b - read 8 bit word from 64 bit address read64l - read 32 bit word from 64 bit address read_cmp - read and compare memory to val reset - Perform RESET of the CPU run - run commands in an environment variable saveenv - save environment variables to persistent storage setenv - set environment variables sleep - delay execution for some time smi - peek/poke SMI devices tftpboot- boot image via network using TFTP protocol usb - USB sub-system usbboot - boot from USB device version - print monitor version watchdog <start | stop | show | pat> write64 - write 64 bit word to 64 bit address write64b - write 8 bit word to 64 bit address write64l - write 32 bit word to 64 bit address