Hi @Kaitlynyau!
Here is a link to the Spotter Firmware - it is for v2.9.0. This link should automatically download the zip file.
https://5311899.fs1.hubspotusercontent-na1.net/hubfs/5311899/Spotter%20firmware%20updates%20page/v2.9.0/Spotter_BM_Firmware_Update_v2.9.0.zip
This is the installer script and here is a link on how to use it.
I am assuming you also saw something like: 235660t [BM_DFU] [INFO] Node 0000123456789876 update status: 0, 12. c(or really 0xc) and 12 are referring to an enum in bm_dfu.h called bm_dfu_err_t. These are the different error codes for bristlemouth dfu. On v0.11.0 this error 12 is BM_DFU_ERR_UNKNOWN_NODE_ID meaning the node id was unknown. I would double check that the node id you have for your bridge is correct. On this version of Spotter/bridge you can check that in the Spotter terminal using bm topo. The first node id will be the bridges.
Best
Victor