Sierra Wireless Modems » History » Revision 4
Revision 3 (domi, 08/15/2018 08:22 PM) → Revision 4/5 (laforge, 10/11/2019 12:21 PM)
h1. Sierra Wireless Modems Sierra Wireless also seems to offer a number of modems that run on MDM9615 or its successors, with Linux inside the module. h2. List of related modems * EM7455 * many others suspected, FIXME. h2. Getting access to the Linux system Sierra Wireless uses a bitmapped NVRAM variable to tell the system which functions to enable. One of these functions is 'adb'. They also implement an AT command to set this variable, but you cannot enable 'adb' there anymore (or maybe you can, using some other password?). This AT command help text is taken from an old memory dump: <pre> #AT!USBCOMP=<Config Index>,<Config Type>,<Interface bitmask> # <Config Index> - configuration index to which the composition applies, should be 1 # <Config Type> - 1:Generic, 2:USBIF-MBIM, 3:RNDIS # config type 2/3 should only be used for specific Sierra PIDs: 68B1, 9068 # customized VID/PID should use config type 1 # <Interface bitmask> - DIAG - 0x00000001, # ADB - 0x00000002, # NMEA - 0x00000004, # MODEM - 0x00000008, # RMNET0 - 0x00000100, # RMNET1 - 0x00000400, # RMNET2 - 0x00000800, # MBIM - 0x00001000, # RNDIS - 0x00004000, # AUDIO - 0x00010000, # ECM - 0x00080000, # UBIST - 0x00200000 </pre> There are other ways to set this and other variables, so the AT comand interpreter restriction is not a show stopper. Note that there are invalid gadget combinations, so you can softbrick the modem by changing this variable. h2. Enable DIAG and AT interface - EM7455 Based on my testing done with the EM7455 (found in Lenovo ThinkPads for example) you cannot use AT commands, because the AT serial port is not exposed. To enable the DIAG interface as well as the AT shell you can try to use the script attachment:swi_usbcomp.pl, "swi_usbcomp.pl" attached, created by Bjørn Mork. It is capable of showing the USB configurations available, and also changing the configuration. Example output - querying the available configurations (the * denotes the active configuration): <pre> ./swi_usbcomp.pl Running in MBIM mode (driver=cdc_mbim) MBIM OPEN succeeded QMI msg '0x0021' returned status = 1 MBIM QMI support verified supports 33 QMI subsystems: 0x00 (1.5) 'QMI_CTL' - Control service 0x01 (1.67) 'QMI_WDS' - Wireless data service 0x02 (1.14) 'QMI_DMS' - Device management service 0x03 (1.25) 'QMI_NAS' - Network access service 0x04 (1.6) 'QMI_QOS' - Quality of service, err, service 0x05 (1.10) 'QMI_WMS' - Wireless messaging service 0x07 (1.3) 'QMI_AUTH' - Authentication service 0x08 (1.2) 'QMI_AT' - AT command processor service 0x09 (2.1) 'QMI_VOICE' - Voice service 0x0a (2.24) 'QMI_CAT2' - Card application toolkit service (new) 0x0b (1.45) 'QMI_UIM' - UIM service 0x0c (1.4) 'QMI_PBM' - Phonebook service 0x0f (1.0) 'QMI_TEST' - Test service 0x10 (2.0) 'QMI_LOC' - Location service 0x11 (1.0) 'QMI_SAR' - Specific absorption rate service 0x17 (1.0) 'QMI_TS' - Thermal sensors service 0x18 (1.0) 'QMI_TMD' - Thermal mitigation device service 0x1a (1.16) 'QMI_WDA' - Wireless data administrative service 0x1d (1.1) 'QMI_CSVT' - Circuit switched videotelephony service 0x22 (1.0) 'QMI_COEX' - Coexistence service 0x24 (1.0) 'QMI_PDC' - Persistent device configuration service 0x29 (1.0) 'QMI_RFRPE' - RF radiated performance enhancement service 0x2a (1.0) 'QMI_DSD' - Data system determination service 0x2b (1.0) 'QMI_SSCTL' - Subsystem control service 0x2e (1.0) 'unknown' - 0x30 (1.0) 'unknown' - 0x31 (1.0) 'unknown' - 0x36 (1.0) 'unknown' - 0xe1 (1.0) 'QMI_RMS' - Remote management service 0xf0 (1.0) 'unknown' - 0xf3 (1.0) 'unknown' - 0xf5 (1.0) 'unknown' - 0xf6 (1.0) 'unknown' - QMI msg '0x0022' returned status = 1 Got QMI DMS client ID '3' QMI msg '0x555b' returned status = 1 Current USB composition: 9 USB compositions: 0 - HIP DM NMEA AT MDM1 MDM2 MDM3 MS NOT SUPPORTED 1 - HIP DM NMEA AT MDM1 MS NOT SUPPORTED 2 - HIP DM NMEA AT NIC1 MS NOT SUPPORTED 3 - HIP DM NMEA AT MDM1 NIC1 MS NOT SUPPORTED 4 - HIP DM NMEA AT NIC1 NIC2 NIC3 MS NOT SUPPORTED 5 - HIP DM NMEA AT ECM1 MS NOT SUPPORTED 6 - DM NMEA AT QMI SUPPORTED 7 - DM NMEA AT RMNET1 RMNET2 RMNET3 NOT SUPPORTED 8 - DM NMEA AT MBIM SUPPORTED * 9 - MBIM SUPPORTED 10 - NMEA MBIM NOT SUPPORTED 11 - DM MBIM NOT SUPPORTED 12 - DM NMEA MBIM NOT SUPPORTED 13 - Config1: comp6 Config2: comp8 NOT SUPPORTED 14 - Config1: comp6 Config2: comp9 NOT SUPPORTED 15 - Config1: comp6 Config2: comp10 NOT SUPPORTED 16 - Config1: comp6 Config2: comp11 NOT SUPPORTED 17 - Config1: comp6 Config2: comp12 NOT SUPPORTED 18 - Config1: comp7 Config2: comp8 NOT SUPPORTED 19 - Config1: comp7 Config2: comp9 NOT SUPPORTED 20 - Config1: comp7 Config2: comp10 NOT SUPPORTED 21 - Config1: comp7 Config2: comp11 NOT SUPPORTED 22 - Config1: comp7 Config2: comp12 NOT SUPPORTED QMI msg '0x0023' returned status = 1 </pre> Changing the configuration is simple: <pre> ./swi_usbcomp.pl –usbcomp=8 ./swi_usbcomp.pl –reset </pre> As you can see ADB cannot be enabled for EM7455 using swi_usbcomp.pl, but at least DIAG and AT shell can be made accessible.
