Catfish hardware
The catfish hardware is based on the Qualcomm MSM8909w chipset. In the picture of the front of the main board with the shield removed, this part is just above the horizontal center line of the board and slightly to the left of the vertical center line. The large part under the bit of rubber or glue is a Kingston 04EPOP04-NL3DM627, which is a combo memory of 4GB MLC + 4Gb LPDDR3 in a 136-Ball BGA package.
Hardware details - front
Outside the shield at the top left of the board is unknown chip #1. A picture of this chip is shown below. Unknown chip #2 is a much smaller chip to the right side of the board.
Hardware details - back
At the top of the board below the two connectors are two chips, shown in a picture below as "unknown chips 3 and 4 on back of catfish." The markings on the chip to the left say:
2310208 VGM41_1 B8214
The markings on the on eo the right say:
K318 AFC3
Toward the bottom of the board are three additional chips. To the left of the battery connector is a chip labeled:
SF 739
With a barcode between "SF" and "739". A closeup photo is shown below as unknown chip #5.
The small unknown chip #6 to the right of the battery connector bears these markings:
75CK371 BQ27431 G1D
In the photo below, it's the smaller chip to the left.
The chip to the right of at the bottom, the largest chip on the back of the board, is a ST71NFCD which is a Near field communication (NFC) controller which includes its own ARM Cortex-M3 microcontroller. A closeup photo of that chip is also shown below.